Mayfly-December Romance

""You can spend the rest of your life with me... but I can't spend the rest of mine with you. I have to live on. Alone.""

- The Doctor, Doctor Who

Large disparities in lifespans between characters can be problematic, especially if their relationship goes into the romantic field. This plays on the very mundane fact one character will probably be long dead of old age before another even starts aging significantly, and the emotional issues it raises. How much this is alluded to is usually related to how concise the story which addresses it is, although fans will often point it out. A few writers deliberately avoid it, while the other extreme, waxing philosophical, usually has an answer from the get-go. The most obvious way out of this is usually to even out the age-bracket on either end. In older fiction, characters may be granted immortality, but recently the reverse is more common.

For the progeny of these pairings, it's even harder to find a compatible mate lifespan-wise, because generally their lifespan is the average of their parents. They'll live longer than the mortal, and shorter than the immortal. Such individuals tend to be rare, so there's no option with "just the right amount of lifespan." Expect the immortal parent to get just as Angsty about dead kids, if not more so.

If the immortal is a vampire, they have an obvious way around this. Although this has a tendency to piss off the would be mortal, or it turns them evil, as opposed to the Friendly Neighborhood Vampire the original was.

Can raise Fridge Logic issues in an Anyone Can Die franchise with a high body count, given how few characters in such series even get the chance to live out a full lifespan.

Anime is known for its often accepting treatment of the subject, due to the Japanese concept of mono no aware; roughly, the beauty of transient things.

I Hate You, Vampire Dad may be the result. May–December Romance is the more mundane version without the mayflies. Compare Reincarnation Romance. Contrast Eternal Love, where both partners are immortal or at least long-lived.

Anime and Manga

 * One of the main plot elements of Crest of the Stars. There is greater focus on this in the manga.
 * Frequently suspected to be a touchy subject in Ah! My Goddess, the matter is only obliquely referred to in original manga and an episode of the 2005 TV show featuring a ghost. This is tricky to pin down though, as we've seen the ladies at different ages for different reasons (flashbacks to Heaven, magical effects, and so on) but it's a matter of Canon that the goddesses' Earthly bodies are three-dimensional projections of multidimensional beings, who constantly refresh their 3-D atomic structure so that Keiichi -- a 3-Dimensional being -- can see them. (See here.)
 * Keiichi is very aware that he is destined to be with Belldandy for the rest of his life, not hers. Interestingly, he asked Peorth about this (in one of the later Manga arcs); he couldn't bear to ask Bell. She fondly answered that they never forget the people that they have met over the ages and cherish them all.
 * In the original Japanese, it was implied that it was Keiichi's innate acceptance and understanding of their relative differences that was part of the attraction he presented to Belldandy and the other goddesses.
 * One interesting Fanfic attempt to resolve this issue postulated that Keiichi's (initial) wish put him into a special cycle of reincarnation, and that in every one of his lives he gets to be with Belldandy and the other players; the story even included a scene where demon antagonist Mara/Marller learns of Keiichi's latest incarnation and muses that it will be good to see the rest of the old gang once again. Other fanfics instead solve the problem by having Keichi ascend to be a god at Belldandy's side, sometimes even going as far as to show the long and stony road required to get there.
 * Another massive crossover fanfic involved a supervillain trying to neutralize the goddesses by killing Keiichi -- which, in their interpretation, would force Belldandy to accompany him to heaven, thus removing her as an enemy.
 * However, it should be noted that goddesses are portrayed as aging (to some extent, we see them as young children in flashbacks), getting sick, getting injured, and will die if their demon doublet is killed.
 * Well, they are higher-dimensional entities whose job is to make sure that all of 11-dimensional reality continues to function properly, so that's just the bodies that they have assumed on Earth. It is also only Skuld that seems to age, so it may stop at will beyond 20-24 or so. As for the doublet system it is either just the manifested 3-D forms that get killed, alternately it takes killing the demon's higher-dimensional self as well, which would naturally cause massive cataclysmic damage to all of reality. Hence, they have a truce, with few exceptions the demons don't actually do much, and they simply stick to sealing each other away for a time. The writer doesn't particularly care about continuity though, so lately each of the groups actually need the power received from granting a wish. It doesn't quite make sense though, and there have been other versions as well, so the original version seems to make most sense and be best adaptable.
 * This is actually part of the conflict in Mamotte Shugogetten's last episodes, where Shao is conflicted about her increasingly romantic affection towards Tasuke, because she is a hundreds-year-old luck goddess who inevitably outlives all her Masters.
 * The ending to Yami to Boushi to Hon no Tabibito is driven by this trope.
 * Unusually, Yokohama Kaidashi Kikou deals with this in a fairly straightforward way: despite her obvious affection for Takehiro, Alpha avoids becoming romantically involved with him because she knows she will outlive all of her human friends. She encourages Makki to pursue him, and eventually settles down with Kokone.
 * The trope was touched on in a side-story manga in the Record of Lodoss War series centering around the human Parn and elf Deedlit (Deedlit's Tale)`, but received practically no attention in the anime version of the story. However, it did get an English lyric song on the the third TV series soundtrack dedicated to it: "Evermore."
 * Played with: Sara and Lottie in Soukou no Strain: both become Reasoners to see their brothers again, because relativistic effects (Interstellar travel means spending time near lightspeed and dealing with the attendant time dilation, since they don't have FTL travel) declares that once they return, the girls will be long dead. It doesn't work out well.
 * One vampire in Trinity Blood is urged to confess his attraction to a human, as humans grow old and die too quickly.
 * Any romance with the Edels in Elemental Gelade falls into this. Aside from a single-episode plot, this is mostly ignored.
 * Played with in Durarara!!. Celty and Shinra have come to terms with their love for each other, however the age issue is never really brought up. Though Shinra has been in love with her since he was four years old. Squick.
 * Averted and played with in Mnemosyne - the main character is an office lady in her early- to mid-30s whose secretary and lover appears to be around half her age, if that. And then we find out the office lady is a Nigh Invulnerable Badass Normal who won't ever die, which seems like bad news for their relationship, until the secretary admits that she, too, is immortal.
 * Mermaid Saga. Even the one relationship that can avoid this has issues thanks to the disparity in emotional age between Yuta and Mana.
 * Played straight in Brigadoon Marin and Melan, where the young Barrier Maiden was sent to earth for her safety. She's taken in by a kind Japanese family, but her sense of time is much different from theirs, and she barely ages at all before the couple die. She also marries their grandson, and she explains that she would die before him and that she, technically, wasn't human. He doesn't care and they get married anyway. Again, she seems as if she's in her twenties by the time he's lying on her death bed in at least his seventies.
 * At least in the manga. In the anime, the situation was somewhat different (and in ways, a lot more confusing).
 * In Fullmetal Alchemist,  have this problem, and he is desperately searching for a way to become mortal so he can die with her. In the first anime, the problem is slightly different, because he's not so immortal after all.
 * In Spice and Wolf, this trope provides most of the angst Holo, a wolf goddess, feels. She's well aware that she'll live much longer than Lawrence (as shown in the OVA leading into season two as well as a couple of episodes in said season). She claims to have accepted this in season two's final episode but whether she truly has or was just being tough is up for debate.
 * In the final light novel
 * Parodied with Isaac and Miria in Baccano! who  and start panicking over the prospect of ... completely oblivious to the fact that.
 * A huge concern for the fans of Kyo Kara Maoh!, a show whose main plot is about ending racism between humans and a race of demons that age at a bit less than a fifth the rate humans do. Fifteen-year-old main character Yuuri is engaged to the eighty-two-year-old Wolfram, and an interracial marriage has taken place without mention of the aging discrepancy. Addressed later in the tragic romance between Cheri and Don Hiri, but Yuuri's aging still seems to have occurred to no one (though he occasionally makes old man jokes to Wolfram in the manga).
 * Given that Yuuri is the demon king, not only in name but in occasional Alter Ego bouts of spectacular magic, it's really not clear that he has a normal human life span.
 * In Sailor Moon, Sailor Senshi live for hundreds of years depending on version. Unless Usagi somehow gave the power to mortals, any relationship the Senshi could have would end with their mate dying way earlier than they.
 * In the manga it's stated that everyone in Crystal Tokyo becomes extremely long-lived.
 * In Immortal Rain, Rain and Machika have this problem.
 * Evangeline McDowell's infatuation with Nagi Springfield in the backstory of Mahou Sensei Negima hit both this trope and May–December Romance from opposite directions. He was in his late teens at the youngest when they first met, while she had been ten for the past several centuries. He was not having any, and eventually sealed her on the campus of Mahora Acadamy to keep her away from him.
 * A common problem in Natsume Yuujinchou when a youkai and a human fall in love.
 * In Spirited Away, this is what would have happened to Chihiro, a human, and Haku, a river spirit.
 * In Inuyasha, the title character is half-demon and thus is implied to live for centuries, while his love interest is a mortal human. The canon never brings up this fairly obvious problem, not even once, leaving Fan Fiction to play with it in various ways.
 * The story introduces us to three hanyou in total. In every case, the mother was human and the father was Youkai. Youkai have a vastly extended lifespan compared to humans and yet in every single case, the youkai parent was killed, leaving behind the human mother as a survivor who had to raise the child alone (although, in Inuyasha's case, his mother also ended up dying when he was young, although he's old enough to have memories of her whereas his father died before he was old enough to form lasting memories of him).
 * In Code Geass, Mao is in love with C.C., an immortal woman who he's been with since he was six. His out-of-control Telepathy (which she is immune to) gives him no other options outside of her.
 * Although his age isn't specified, Isshin Kurosaki is a former Captain-level Shinigami. Masaki was an ordinary human, as far as we know, and still very much alive (until her death at the hands of the Hollow Grand Fisher). Think about it for a second.
 * Not exactly. if she had a normal death, instead of being killed by a Hollow, it's entirely possible she would have gone to the soul society.
 * And since he  she's probably somewhere in the Rukongai right now.
 * Karin has the relationship between Karin Marker and Kenta Usui. She does realize that she will outlive him as she is a vampire and he is a human.
 * Hana, the 14-year-old girl (for most of the story) of Hana to Akuma is in love with Vivi, a demon who will live centuries longer than her. Naturally, he is constantly tormented; he hates celebrating her birthday because it means she's closer to death, and frequently counts down her remaining years in panic. When he comes to return her romantic affection, he tries to leave to let her live a normal life.
 * Ojamajo Doremi: During the Mo~tto! season, it is revealed that this is the reason the Witch Queen from two reigns ago goes crazy and creates all kinds of troubles, such as cursing Hana-Chan and creating the Smiling Moon rule, the Magic Frog Curse, and the Cursed Forest.
 * Tayutama the main character expects this trope to happen to himself with his wife Mashiro . The odd ending probably recreates the trope straight but isn't explored.
 * Pita-Ten being an angel Misha is extremely long lived or immortal. This is only an issue in the manga but not the anime where she Kotaro is the reincarnation of Misha's love which is why she greets him at their first meeting with 'Let's go on a date!' she's waited some 80 years to see him. Since that isn't the case in the anime it makes her seem more of a Cloudcuckoolander.
 * Maquia: When the Promised Flower Blooms looks at this trope through the lens of a different kind of love, when very-long-lived Maquia resolves to raise the orphaned infant Erial. The movie proceeds to show us how suddenly becoming Erial's mother and knowing that she will outlive him changes Maquia.

Comic Books
"Doom: "He was mortal. You are not. Soon time would have struck him down as surely as what you accuse of.""
 * In Top Ten, a satirical Deconstruction of the superhero comic, a minor background action outside a courthouse turns this on its head. Two men feud over "The Immortal Woman", because they were extremely shallow, and wanted to have a trophy wife who would remain supermodel-perfect for their entire lives, and thus not need to be dumped and replaced after a few years.
 * In The DCU comic Infinity, Inc., a subplot of the "Stream of Ruthlessness" story arc involved Earth-2's Wonder Woman seeking a means to restore the youth of an aging Steve Trevor, whom she had married after World War II.
 * Similarly, in the late 1980s comic book mini-series Squadron Supreme, Power Princess (a pastiche of Wonder Woman) is shown caring for her septugenarian husband, whom she married in the 1940s when she first left Utopia Isle.
 * Joe Kelly repeated this in a JLA comic where Wonder Woman is shown taking care of an elderly and dying Bruce Wayne in a dream sequence.
 * The Sandman included the character of Hob Gadling, who was made immortal. In one of his stories, he states, while weeping next to the grave of one of his latest companions to die, "I thought we'd have longer. It never gets easier, people you love not being there any more."
 * Dream's frequent though illegal romances are all of this form, since Dream as one of the Endless is as old as the universe (10 billion years for Neil Gaiman's purposes) and so even goddesses and really old witches will be outlived. Though he probably usually manages to destroy the relationship before old age becomes an issue. His brother Destruction has a similar relationship, with a goddess who only lived for a few thousand years.
 * In the Heroes online comic book, one issue shows the many wives of Adam Monroe (and also spoils the end ofHeroes volume 2, so watch out). One of these romances even sort of works out. Adam and his wife stay together though they must pretend to be mother and son, and later, grandmother and grandson.
 * The twist is  Sadly this twist was ignored, as
 * The DCU Elseworlds comic Kingdom Come shows a still-youthful Superman long after Lois Lane's death, and eventually.
 * He's still more or less in his prime, but his hair has begun to grey at the temples. And it's not like Lois died of old age, she was.
 * This is an issue in Watchmen, in which the immortal Dr. Manhattan is fully aware of the fact that his girlfriend will continue to grow old and he will not. His first girlfriend, Janey Slater, is also aware of this, and it eventually causes the end of their relationship when he leaves her for the much younger Laurie. Of course, Dr. Manhattan knowing beforehand that this would happen doesn't help things.
 * Lampshaded by Doctor Doom when he confronted  who wanted to avenge the death of her beloved,.


 * Elf Quest just plain tears this up. The elves, magical immortal creatures, are the descendants of alien shapeshifters. After crash-landing on the planet with two moons, the aliens tried to survive: some by living as primitive humans, one by killing everything else, and one by turning into a wolf and becoming the ur-mother of a tribe of half-elf-half-wolf babies (a lot of which... didn't survive). 10,000 years later, the comic's main character Cutter, a direct descendant of the mortal wolf-blood line, pairs up with Leetah, a pure immortal elf. Drama ensues.
 * Heavily deconstructed during the second half of the main quest: another 10.000 years pass, during with most of the mortal elves decide to go into magical hibernation. One family of elves (who happen to look most like the "classical" elf of Western mythology) decide not to, and try to live a peaceful and fulfilling mortal life. The thing is - they just can't stop counting the years. Their youngest son, who was brought up by mortals in a tribe of immortals, decides that hibernation is a better alternative, because counting the years would make him go insane.
 * And then Winnowill, the series' main villain, discovers that her healing powers allow her to make mortal elves immortal. Against their will. And teaches Leetah, the hero's lifemate, that her own healing powers would allow her to do the same. After being kidnapped 10,000 years into the future, and believing (with good reason) that all of their friends are dead, Skywise (the hero's best friend) asks Leetah to make him immortal... only to find out several hours later that everyone they know is still alive.
 * At one point in the comic, Leetah is briefly - very briefly - tempted to "cleanse" Cutter in his sleep. She utterly hates herself for even thinking about it.
 * Aside from the main characters, there are many, many mortal/immortal pairings in Elf Quest, and even three cases of humans being adopted by elves.
 * Invincible's Dad, Omniman revealed that his kind can live for over a thousand years so he did his best to consider his human wife as more of a pet.

Fan Works

 * Though the original creators never alluded to it due to the crackishness of the pairing, shippers of Yuffie/Vincent from Final Fantasy VII have done this trope straight into the ground.
 * Same with Vincent/Tifa...rare as it is.
 * In the Transformers Film Series fandom, it's been touched upon multiple times concerning the Sam/Bumblebee pairing.
 * Rarer, but was still touched upon, in the SarixBumblebee pairing.
 * Touched on in the animated video for the Touhou remix "Alice -> Dere" between the Youkai Alice and the human Marisa.
 * Indeed, this trope seems to be the general source of angst in Alice x Marisa pairings (the famous "Marisa Stole the Precious Thing" remix by IOSYS, who did the one above as well, contains the line "You and I are of a different kind"). Which is all good and well, until Fridge Logic sets in and you realize that, under current canon, Alice USED to be human but became youkai via magical research, and Marisa has access to Alice's notes/materials/Alice herself, AND Marisa has been independently searching for an immortality potion.
 * The topic is likely to come up in any of the human/youkai pairings. Even in the case of a certain immortal human, who will outlive the Youkai.
 * By far the most common is Sakuya, even without involving romance, as she is the only human in the relatively large Koumakan Cast Herd, meaning her expected lifespan is considerably less than their's. However, there is also speculation that Sakuya is a Lunarian, who are incredibly long-lived (Eirin and the Watatsuki sisters are at least several millennia old).
 * Another Touhou remix that uses this heavily (in a very beautiful waltz) is "The song of a Broken Youkai who loved a human." I wonder what it could possibly be about...
 * A lot of the more...mature fanfic written for Star Trek: The Original Series touches on Sarek and Amanda's relationship and how Sarek would handle Amanda's death.
 * There are a couple of not exactly canon Star Trek novels that touch on them as well. The Vulcan Academy Murders is basically all about their relationship, and human/Vulcan relationships in general. It uses Applied Phlebotinum to age Amanda back down and give them another thirty years or so.
 * It's also a misogynistic disappointment as a mystery.
 * Since Jareth and Sarah are the Fan-Preferred Couple of Labyrinth, this is always an issue which is usually solved in one of several ways: most of the time, Sarah somehow becomes a fae (since everyone assumes Jareth is one), or sometimes just an immortal human. Some stories write it off by saying that all humans in the Underground age extremely slow. Less often, Jareth will actually become mortal and join Sarah above ground, and very rarely, Sarah remains mortal and the relationship ends when she eventually... well, dies.
 * There is a lot of Sailor Moon fanfiction that deals with this concept, since only the manga says normal humans become long-lived in the future and even if they do live a long time, they still don't live as long as the Sailor Senshi. One large series by author Bill K. even features two marriages within the Senshi to normal men who, obviously, die way sooner than their Senshi wives. Jupiter and Mercury react accordingly... and then hook up, so there's that.
 * Axis Powers Hetalia fics sometimes play with it too, usually focused on the relationship between national personifications and their most beloved historical figures. France/Joan of Arc is probably the most common, given the later's five-second appearance in the show; but lots of famous rulers or national heroes get represented. There was even heartrending fanvid montage of a bunch of them floating around for a while.
 * Justice League fanfiction dealing with Batman and Wonder Woman is often about this and Diana dealing with Bruce's inevitable death.
 * The "Tragedy of Long Life" pool on Danbooru is dedicated to this trope.
 * This is a very common trope for shipping fanfics concerning the Princesses in My Little Pony: Friendship is Magic. Being the only two immortals (Alicorns) revealed so far, a common qualm about them getting into a relationship is usually along these lines, unless it is a Yuri pairing of either of them with Twilight Sparkle, who has enough magic to presumably make herself immortal if she wanted to, or with each other, a pairing known as Princest.
 * Due to it being unclear how long a dragon's lifespan is, there's speculation a Spike/Rarity relationship might wind up becoming this.
 * In Andromeda, two out of the three women on the main cast were an avatar of a star (it only became apparent rather late in the series, but she was believed to be older and immortal much earlier), and a just about immortal android. This made the trope common enough.
 * Generally (surprisingly) not brought up in Bleach fan fiction, mostly because it's usually Ichigo/Someone and he's a Shinigami as well and technically can "live" just as long. The age gap might be mentioned in passing, but that's it.

Films -- Animated

 * Milo and Kida in Atlantis: The Lost Empire. The former is twenty-something, the latter over 8000 years old.
 * One hopes that either she's aware she doesn't get to keep him, or donning the crystal and becoming a resident allows him to achieve the same life expectancy.
 * A creative (and soul-destroying) non-romantic variation on the theme appeared in Toy Story 2: Jessie, as an unchanging toy, "outlived" Emily's childhood.
 * And continued in Toy Story 3 where Andy has grown up and no longer needs his toys.
 * This is the reason given in Bluth's The Secret of NIMH as to why Jonathan Brisby never told his wife anything about NIMH; the intelligence-boosters also slowed their aging. From a mouse's perspective, Jonathan was near-immortal, and he couldn't bear to tell her that he would watch her age and die while he stayed young.

Films -- Live-Action

 * The Hunger. Ancient, immortal vampire Miriam turns her mortal lovers into vampires, who then live with her for a couple of hundred years. They then wither and age rapidly to a near paralytic state, and she files them away in coffins in her attic. She does show some regret over this.
 * Reflected in the song "Who Wants to Live Forever?" by Queen which was, appropriately, written for the soundtrack of Highlander.
 * A Mayfly-December Romance is almost inevitable for the immortals in the film series, as they will naturally outlive any human love interests, and immortal-to-immortal romance is problematic too, as they are all engaged in a deadly battle royale with one another that won't end until only one is left.
 * Ray and Mary of Hancock also have to deal with the Mortal/Immortal issue. Although at first after the reveal it seems like it might be a dealbreaker for Ray and the issue is never explicitly resolved onscreen, they are seen at the end together and jokingly reviewing the truth about famous historical figures.
 * This trope is one of the central points of Bicentennial Man, in which the main character is a robot who wants to become human.
 * The Fifth Element
 * With Leelo being the December here. (Being at least a multiple of 4000 years old...)
 * Life in a Day, starring Michael A. Goorjian and Chandra West.
 * To extremes in The Man From Earth. Main character John Oldman appears to be 35, but is actually a Cro-Magnon caveman who has lived through 14 000 years. This naturally causes difficulty in his romantic relationships, as he has to abandon each woman after a few years so that people don't catch on to his immortality. References are made to various women he has loved, including one of the films main characters, Sandra, a historian in her 30's.
 * His children are completely mortal though, so there's no worry about them.
 * of The Green Mile turns out to suffer from this.
 * Blade Runner.
 * Jack Bonner and Kitty in Cocoon.
 * In We Are the Night, vampiress Charlotte acts pretty dissociated from her Sire Louise. Turns out the reason for that is that . Later in the movie we see
 * Also somewhat counts for, since the vampiress who sired her died and left her restless and heartbroken.
 * In the second Night at the Museum movie Genki Girl, Manic Pixie Dream Girl Amelia Earhart, or rather a magical construct of the XX century aviatrix, tries actively to pursue a romance with Larry Dailey, the protagonist. Larry instead tries actively to spurn her, knowing that the magic infusing her with life will wane at dawn, thus wanting to avert this scenario, sparing Amelia the knowledge of her overtly short "new lease" at life.
 * Double aversion:
 * Two examples from Queen of the Damned:
 * Jesse and Lestat. The first is a human woman in her twenties, the second a vampire several hundred years old.
 * Lestat and Akasha. Both of them are vampires, but Akasha is thousands of years older than Lestat.
 * In Fred Claus, Santa Claus's immortal immediate family suffers from what the article calls the "Highlander Complex": "They will have to watch their friends and relatives wither and die right before their callous, eternal eyes."

Literature

 * One of the better-known cases is the romance between Aragorn and the elf maiden Arwen Undómiel in Tolkien's The Lord of the Rings. It was a relatively minor subplot in the novel (their full story is in the Appendicesto The Lord of the Rings), but became a much larger part of the later films.
 * Giving numbers: he is 88, she is 2798 years old.
 * When they first fell in love, he was a teenager and she was still over 2700 years old.
 * To be more specific, Arwen is descended from a line of mixed heritage involving humans, elves, and even a Maia. Her paternal grandparents were granted the choice of whether they would live as elves or as humans, and the opportunity to choose was passed on to each of their descendants. In the Middle-earth setting this means that she can choose to either be a mortal or an immortal. The main source of angst in this choice, however, is that the two races do not share the same afterlife. Elves, even if killed, travel to the Undying Lands in the west and are usually resurrected, eventually. Humans, upon death, disappear from this world and their fate is unknown. Thus her choice is to be forever sundered from Aragorn, or forever sundered from her family. Like all resolutions in Tolkien's works, either choice is bittersweet at best.
 * And let's not forget that Aragorn is also descended from that same line! The first King of Numenor having been Elros... Elrond's brother! There's dozens and dozens of generations in between; which is itself another example of this very trope. Leads to an interesting question too: apparently if the parents decide to be elfy, their children can still pick, but if they decide to be human, they can't... might have to do with when they decide in relation to when they have kids, I suppose...
 * At least in The Films of the Book, Elrond tells Arwen that even as a mortal, she will far outlive Aragorn (keep in mind that Aragorn himself, as a Dunedan, lives 210 years) and live alone after Aragorn's death for a very long time.
 * That sequence in the films is basically what happens in the book, although I don't think Elrond specifically warned Arwen of it. Aragorn chooses to die when his time's up, and Arwen leaves her daughters and son behind to go to Lorien and spends her long last years alone.
 * Though, strictly by the word of the book, it's not clear how long this is- in fact, by the timelines it may have been mere months. (Arguably, Arwen entered a state of severe depression and starved herself to death, though such mundane explanations are hazardous when dealing with elves. Tolkien certainly believed in 'death by broken heart' even in real life, since his mother's death- while his mother died from diabetes (hard to treat in those days), he always believed that her grief at becoming estranged from her family shortened her life.)
 * This trope surfaced often in Tolkien's work. From The Silmarillion, we have Beren and Lúthien and Idril and Tuor.
 * Mixed couples overall are very rare (known are five and a half, and only three got together permanently). There is one male elf/female human Star Crossed couple - in fact the very first elf-human romance known to us: Aegnor (Galadriel's brother) and Andreth (woman of the Edain). And Aegnor pretends not to return her love, so he won't have to watch her age, and he feared that if the Siege of Angband broke then it would be very likely that he would die in battle (and he was right).
 * Also in the History of Middle Earth, this trope played beautifully in the marriage of Aldarion and Erendis on Númenor, lost home of the Dúnedain. Númenoreans had a typical lifespan of 100 to 200 years, but those of the royal house lived two to three times as long. Aldarion was the 6th king of Númenor; Erendis his wife was not from the royal house. Aldarion's long lifespan and his tendency to make multi-year voyages while Erendis continued to age rapidly drove a wedge in their relationship. Their problems in turn embittered their daughter, the future queen Tar-Ancalimë. This proved to be the first small step in the eventual downfall of Númenor.
 * Note that all of the mixed couples in the LotR Verse are human/elf, despite the fact that both hobbits and dwarves are usually on good terms with their immediate human neighbors and with one another. As both these species have longer lifespans than humans, and dwarves live far longer than hobbits as well, this trope may be part of what's discouraging interracial relationships among the three mortal races.
 * Although I still suspect that the description of the Men of Bree ("brown-haired, broad, and rather short"), and the prevalence of atypically "botanical" surnames among the Bree-Hobbits, can be taken as a deliberate implication that there has at least in the past been interfertility between the Bree-land's "Big Folk" and "Little Folk".
 * Potentially also (from The Lord of the Rings) Faramir and Éowyn, since he had some Númenorean blood and, despite being thirteen years older than her to begin with, could have outlived her by decades. We aren't given a date of death for Éowyn, but Faramir lived well into his second century and it's extremely unlikely Éowyn lived nearly that long.
 * In Tuck Everlasting, 17-year old Jesse Tuck tells Winny to drink magic water to gain Immortality when she reaches his age.
 * Jesse's older brother Miles was once married. When she realized that she aged while he stayed twenty-two, she accused him of selling his soul to the Devil.
 * While it's not really romantic (unless you get into fan fiction), dragons in the Temeraire series are capable of far outliving their much-adored riders. It's even suggested to Laurence that he hurry up and have a child, so that the transition will be easier when Temeraire is forced to move on to another captain after Laurence's death.
 * Becomes a problem for both Cindy and Frederick in Stationery Voyagers. Mosquatlons can live to be 800 years old, whereas Whiteouts have about an average human lifespan. Cindy's boyfriends all seem to have suicidal tendencies, making her time with them even shorter. Frederick and Joli are generally on the down-low about their relationship; and have come to merely accept the fact that Frederick will go from looking 27 to looking no older than 40 at the same time that Joli turns 70. The fact that Joli is 16 and Frederick somewhere between 215 and 250 is explicitly pointed out by Cindy as being a bit creepy; even though she's got a lover who's about 26, while she's 300 and looks about 35.
 * Philip Pullman's His Dark Materials features the witches, who live for roughly a thousand years, and so are continually having their lovers, husbands, and mortal sons dying on them (their daughters are always witches). One of them describes this as being very painful, and suggests that they eventually die when they can't take losing anyone else.
 * Drizzt Do'Urden, in his series of novels by R.A. Salvatore, spends much of the series trying to prevent himself from getting close to his human friend, Cattie-brie, knowing that he will outlive her by centuries, but eventually falls for her anyway.
 * The premise of the fantasy novel Sirena, where the titular protagonist is one of the Greek Sirens who will become immortal after having sex with a human man. Falling in love with said man, however, makes the irrevocable gift a curse.
 * Seen in The Inheritance Trilogy, where age is given as the main reason Eragon can't have a romance with Arya. This doesn't really make sense, though; Arya may be eighty or ninety years older than Eragon, but as a Dragon Rider he will have a similarly extended lifespan.
 * It's more of because Arya is mentally decades older than Eragon in the present time that seems to be the biggest problem...
 * I don't see the problem there, for if they both live thousands of years a few mere decades are a trivial matter.
 * I don't think she was considering it in that way, or in the long run (I mean, at the end of Inheritance ), she was more commenting on relative emotional maturity, as proved by the comparative making of fairths that Eragon performs; the first one being in Eldest  and the second being in Inheritance.
 * He's fifteen.
 * Eragon has actually used the trope as the reason why he can't get romantically involved with humans. The trope doesn't even apply to the Arya situation because the two never knew each other UNTIL he was a Dragon Rider (and therefore immortal).
 * Not that it seemed to stop Eragon's mother and . Well, as was later revealed, Eragon's mother and . They're both  All a bit squicky
 * Ended in David Eddings' Belgariad. Polgara
 * This trope is touched upon in the Robert A. Heinlein novel Time Enough for Love, which has as a main character an essentially immortal man, Lazarus Long (born Woodrow Wilson Smith, around the turn of the 20th century). Specifically, the story involving Dora.
 * Lazarus specifically states that it's a bad idea for long-lived Howards such as himself to marry people with normal lifespans (or "ephemerals"). Dora was possibly the only time he broke that rule.
 * This subject causes much angsting in the Dragonlance novels, in which Tanis Half-Elven loves both an elf who would long outlive him and a human who would die while he was still young.
 * The Xanth novels are full of this : X(A/N)th (male demon)/Chlorine, Demetria (female demon)/Veleno, Jewel (nymph)/Crombie, and others. Averted, as Xanth is also absolutely full of Fountains of Youth.
 * And X(A/N)th, being literally omnipotent, can do anything he damn well pleases, including extending a human's life indefinitely.
 * One of Clive Barker's Abarat books has an unusual twist on this idea: on the island of Nonce, where the heat and storms cause the rain forest there to grow and decay incredibly quickly, a man has fallen in love with a plant. Plant-woman. However, her life is very brief compared to his (a few hours, at most, with the island's weather), but she also always produces a seed that is a fresh new version of herself. So he spends his whole life clambering over the island all day, looking for her newest sprouting, even though she won't remember him, so that for however brief, they can be together.
 * Bella of Stephanie Meyer's Twilight series is very conscious of this trope and has spent most of three books trying to convince her immortal vampire boyfriend to bite her to avoid this.
 * In the Star Trek: New Frontier Expanded Universe series, Selar (a Vulcan with a lifespan of about 250 years) mates with a Hermat (with a 40-year lifespan...and both sets of genitals). Selar carries a child to term...and it turns out he has the lifespan of an Ocampa (10 years, if he's lucky.) In the most recent novel of the series, Treason, this gets fixed, though ironically (for multiple reasons)  It's not a happy book.
 * A Star Trek: The Next Generation novel, Immortal Coil, dealt with this in connection with Data. Taking place not long after First Contact, the plotline includes Data's emotional realization of what he's always known intellectually - he will almost certainly outlive all of his friends on the Enterprise. And then another set, and another. The actual plot of the book assuaged these fears . And then Nemesis happened...
 * In the Star Trek: The Lost Era novel The Buried Age, Jean-Luc Picard enters into a relationship with an alien known as "Ariel" (real name Giriaenn). Ariel is effectively immortal, and has been alive longer than humans have existed as a species. Her relationship with Picard was genuine while she had amnesia; when her memory returned, though, she began stringing the "innocent child" along as part of her master plan. Being as old as she is, she's an complete expert at manipulation, plus her people are naturally designed for it anyway.
 * The long-lived Tiste Andii, Korlat, and the already fairly old Human,, in Malazan Book of the Fallen. In fact, it's stated that Tiste Andii tend to have relationships with shorter-lived races, finding 200 years of marriage to their own kind wearisome and a bit pointless.
 * Stardust features this. Mortal human man, immortal ex-star in human woman form -> dead man and still immortal star regent of their kingdom.
 * In the movie they got around this handily by playing on the "heart of a star" thing, i.e. one who has the heart of a star will live forever. In the films they claim that Yvvaine had "given" her heart to Tristan/Tristran, and therefor they will both live happily forever after.
 * The Hero and The Crown has an interesting variant. Luthe is a super master mage and at least 100 generations old, probably older. Aerin is 20 years old but magically powerful, and capable of being "not quite mortal" herself.
 * Anne Bishop's Black Jewels Trilogy has the pairing of Daemon and Jaenelle. Daemon was about 1700 years old when Jaenelle was born. This is a source of much frustration when  Balanced a bit by Jaenelle being   and Daemon's race being long lived so that he's the equivalent of about 30 years old. But
 * Also Jaenelle is 100% human, so she'll live maybe sixty/seventy more years after The Queen of Darkness and Daemon could conceivably live to be twice or more his original stated age of 1700 years.
 * There's also Daemon's half-brother (and Halfbreed) Lucivar who is about Daemon's age and marries a woman who appears to be only about 300 years old.
 * That being said we must remember that he marries another Eyrien, so their lifespans are (theoretically, anyway) roughly equivalent.
 * And then there is Saetan and his several lovers, including Casandra, who was mortal and would have died if she hadn't become a Guardian, Hecatah, who and Sylvia,.
 * Subverted in The Redemption of Althalus, where the goddess Dweia and human protagonist Althalus fall in love, but the problems are resolved early on when Dweia reveals her ability to control time, letting her and Althalus to stay together as long as time itself exists.
 * In Susanna Clarke's Tom Brightwind or How the Fairy Bridge Was Built at Thoresby (set in the Jonathan Strange & Mr Norrell universe), the eponymous character has one of these with his human wife, but it sours due to his fairy fickleness: "At fifteen... Tom had constantly compared her to a kitten. In her twenties she had been a swan; in her thirties a vixen; and then in rapid succession a bitch, a viper, a cockatrice, and finally, a pig. What animals he might have compared her to now no one knew. She was well past ninety now and for forty years or more she had been confined to a set of apartments... while her husband waited impatiently for someone to come and tell him she was dead."
 * Norman Spinrad's short story Deathwatch examines a future in which humanity develops a mutation that prevents aging... but not everyone has it. Warning: this story has been known to cause blurry vision in even the most stoic readers.
 * In the Mercy Thompson universe, werewolves are immune to old age and disease and can live for centuries  barring injury and insanity. The werewolf Samuel Cornick has had three human wives, each of whom died of old age. Another, unnamed werewolf in Cry Wolf is shown kissing his elderly wife who was initially mistaken for his grandmother.
 * Several times in the Symphony of Ages. The Cymrians live shorter lives with each generation, starting with immortality at generation one. This presumably causes true mayfly romances, but the most visible case is Tristan Steward and his consort Prudence. While they grew up at about the same rate, she starts showing her age and he remains youthful.
 * Subverted and reversed in Glen Cook's Dread Empire series. Varthlokkur is an immortal wizard who is able to use his magic to find the woman he will love. He waits millennia for her to be born, getting married once or twice for fun along the way.
 * In Conn Iggulden's Emperor series, Caesar has a love affair with Servilia, his best friend's mother. Problematic since he needs a son and she is too old to get pregnant.
 * Salamander/Ebañy in Katherine Kerr's Deverry series is a half-elf whose wife dies and is reincarnated in a new body. (Reincarnation is a big part of the Deverry books.) When he finds her again, she is a teenager, and he's about 100. He sees no particular reason not to marry her again - as he points out to his doubting friends, there aren't that many half-elfs around, and this way they might actually live to grow old together.
 * Also Dallandra and Aderyn, she is an elf, he is human. Made worse by, then a partial subversion when
 * In Dan Simmon's Hyperion, Merin and Siri from the sub-story, "The Consul's Tale", are engaged in a Mayfly-December Romance where Merin, who is a crew member on an interstellar construction ship responsible for building a farcaster gate above Siri's homeworld of Maui-Covenant, must watch his love progressively wilt away as he travels back and forth to the planet at relativistic speeds, all the while remaining young himself.
 * In the Night Huntress series, this occurs between Bones, the two-hundred-twenty-year-old vampire, and Cat, the twenty-year-old half-vampire.
 * In The Apocalypse Troll by David Weber, Ludmilla Leonovna is effectively immortal thanks to the Healing Factor her symbiote grants her. So when she falls in love with a normal man, she's very aware of the fact that she'll outlive him.
 * In other series by David Weber, we see this pop up a lot in platonic forms. In Safehold Nimune/Merlin is in a robot body with potential life in the thousands of years, she/he's injected his/her friends with nanites that will give them perfect immunity to infectious illnesses and cancer, but doesn't dare give them life extension treatments because their very public life makes it impossible to do so without it being noticed. In The War Gods we have Wencit whose well over a thousand years old. He also knows the results of how all crossbreeding between the 5 races works, and the other races all out live men. Half-elves only marry half elves or full elves else their children will be too human and not get the Elves' life spans.
 * Also comes into play, though not in a romantic sense, in the Honor Harrington series. Honor herself, and everyone else in Manticore, has ready access to Prolong, a treatment that pushes human longevity up to several centuries...if it's administered at a young enough age. The people of Grayson, the planet which adopts Honor as its own, only get it in the present, and many of the people she gets close to are too old for the procedure and thus she'll outlive them by a considerable margin.
 * Part of the tension between Harry Dresden and Karrin Murphy in The Dresden Files stems from this, as she is a vanilla mortal and he is a wizard who will live for several centuries. Murphy even cites this in Proven Guilty as one of the issues in her relationship with him.
 * One of the eponymous AI tanks in the Bolo universe bitterly reflects upon this when she realises that her commander has been treating her as a human woman, not a multi-thousand-ton, fusion-powered, functionally immortal battle tank
 * In Octavia Butler's Wild Seed, protagonist Anywanyu had many husbands throughout her unnaturally long life, both she and her lovers seemed at terms with this.
 * In Myst: The Book of Ti'ana, Atrus (not the one from the game, but his grandfather) starts to become romantically involved with Anna. His father Kahlis reminds him that the extended D'ni lifespan will mean that he will outlive her by centuries. However,.
 * Played straight and subverted in Cordwainer Smith's The Queen of the Afternoon. Laird, who is basically immortal due to rejuvenation treatments, marries a woman who is unable to be rejuvenated. When she grows old and dies, he married her sister, who has the same problem, but when she is dying, he realizes that.
 * Black Dagger Brotherhood: Both Mary and Jane were humans hooking up with vampires, so Mary and Jane.
 * In Cassandra Clare's Mortal Instruments series,
 * The Adoration of Jenna Fox has
 * In The Wheel of Time, this trope is why Aes Sedai rarely marry: they know that they will far outlive their husbands, and probably their children.
 * In John Green's new book The Fault in Our Stars, Hazel, the sixteen-year-old protagonist, diagnosed with terminal cancer, has an uncertain number of years to left to live, but probably not many. Then she meets and falls in love with a seventeen-year-old Augustus, who is well into remission and will likely live a normal number of years.
 * In Holly Black's Modern Faerie Tales there is unbelievable quantities of this, most notably in Valiant between Val and Ravus, who actually comes out and says that she will be dead in "one faerie sigh", but they are still hooked up.
 * For the first bit of Tithe we assume there will be some of this between Roiben and Kaye, which is solved when.
 * Nicholas Sparks' A Walk to Remember features a young man who marries his high school sweetheart when she's dying of cancer, leaving her dead at the age of nineteen mere months after their wedding while he lives a normal lifespan.
 * For the first bit of Tithe we assume there will be some of this between Roiben and Kaye, which is solved when.
 * Nicholas Sparks' A Walk to Remember features a young man who marries his high school sweetheart when she's dying of cancer, leaving her dead at the age of nineteen mere months after their wedding while he lives a normal lifespan.

Live Action TV
"The Doctor: I don't age. I regenerate. But humans decay. You wither and you die. Imagine watching that happen to someone that you .. Rose: What, Doctor? The Doctor: You can spend the rest of your life with me... but I can't spend the rest of mine with you. I have to live on. Alone. That's the curse of the Time Lords."
 * The Doctor in Doctor Who tends to avoid becoming too close to his companions, due to what he calls "the curse of the Time Lords" - a companion could spend their whole life with him, but he couldn't spend his whole life with them (see quote), being "immortal, barring accidents". An episode of the new series, "School Reunion", explored this issue in detail by focusing on aging ex-companion Sarah Jane Smith, while another, "The Girl in the Fireplace", gave the Doctor a poignant Mayfly-December Romance with Madame de Pompadour.

"Laas: It won't last. Odo: The fact that your relationship failed doesn't mean mine will. Laas: True. If you're very lucky, you'll get to watch her grow old and die."
 * The Third Doctor's relationship with Jo Grant had shades of this. Their relationship was never quite romantic (unless you consider being tied up together romantic), but he did seem awfully disappointed when she ran off and married a man she described as a younger version of him.
 * Worse still, according to Jo, she never stopped running, hoping she'd see the Doctor again someday.
 * Subverted in "Flesh and Stone", when the Doctor raises this trope as a defence to Amy's romantic overtures: "Aw, you are sweet, Doctor, but I really wasn't suggesting anything quite so long term."
 * Played to the very end on Babylon 5 with the Minbari Delenn and Captain Sheridan. Not only do Minbari outlive humans by decades, but Sheridan's return from being Not Quite Dead shaved thirty-something years from his lifespan, leaving them a scant 20 years of married life. Notable for also showing Delenn decades after John's death.
 * A bit of irony is that it may in fact have been Sheridan that out "lived" Delenn as his body was never found, only a sealed empty ship that had him entering it but never exiting it.
 * Valen's body was never found, either, even though he was entirely mortal. The batting record for members of the One being ascended to a higher plane are therefore 2 out of 3. Draw your own conclusions about Delenn's ultimate disposition.
 * Lorien mentions this trope in a conversation with Susan Ivanova. He is the First One, and the last of his kind. He says that being immortal is to leave behind everything you care for, and that love is transitory. According to him, only short-lived species can imagine that love is eternal. He recommends that she embrace that wonderful illusion.
 * Due to the great difference between Vulcan and human lifespans on Star Trek, Spock's father was sure to outlive his mother by many years. (This wasn't addressed in The Original Series, but the Vulcan lifespan may not have been decided at that point.) Sarek has a different human wife, Perrin, in The Next Generation, so Amanda must have died between the generations, but we don't know when.
 * Actually, it was hinted at in Journey to Babel, when McCoy was surprised that Sarek was retiring after the mission -- "after all, you're only a hundred and two."
 * The same issue comes up with Klingon/human relationships. Again, we've never seen this addressed, but that's probably because humans who marry Klingons (especially Worf) don't usually get to die of old age.
 * Worf's more prominent (and only non-Klingon...er...Half-Klingon) marriage was to a joined Trill, which confuses, and, depending on one's interpretation of the joined Trill/Symbiont relationship, laughs in the face of the whole matter. (None of the major Daxes have had any problem with long-term couplings with persons who aren't joined Trill.)
 * On Star Trek: Deep Space Nine, the changeling Laas brings up this trope while trying to convince Odo (a changeling whose species has an incredibly long lifespan) to leave Kira (a Bajoran with a roughly human-like lifespan) in order to join Laas in locating the rest of The Hundred.

"Ianto:"
 * Star Trek: Voyager had a couple of these. For most of the first three seasons, Kes, whose race has a nine-year lifespan, was in a relationship with Neelix, whose life expectancy was apparently normal. Kes's replacement, Seven of Nine, had her own age issue—she was only six when the Borg assimilated her, making relationships with the adult crew somewhat dubious. The exception was the Doctor, who was technically only a few years old himself. Thus Doc/Seven (teased, but never followed through on—a true shame as it was probably the only 'ship in the show that demonstrated any real chemistry) was a rare example of a Mayfly-December Romance that looked ickier than it was.
 * Explored also in the episode where Kes is traveling backwards in time, so we see an alternate future where Kes is married to Tom Paris while his friend Harry Kim is married to Kes's daughter.
 * An early first season episode of Bewitched focused specifically on the issue, with Samantha (apparently) admitting she will still appear to be in her twenties when Darrin is in his seventies. The dilemma is solved when Samantha uses her magic to age along with Darrin. It is unclear whether this would include her actually dying with Darrin instead of living centuries after his death, but for her to shorten her lifespan so radically to age as Darrin ages would provide yet one more reason for Endora's continual efforts to turn Samantha against Darrin.
 * in Buffy the Vampire Slayer, Buffy's relationship with Angel was a mortal/immortal case. This didn't bother them much, until the Big Bad and then Buffy's mom brought it up just in time for the season finale. Angel ended up leaving Buffy for her own good... and the age issue in human/vampire relationships was apparently forgotten by all concerned at that point. (It certainly didn't figure in either Buffy/Spike or Angel/Cordelia.) Of course, the only reason they came up for that reason of Angel leaving Buffy was because they had to somehow get him out of Sunnydale for his spinoff show.
 * It's fairly clear Buffy never intended anything other than a sexual relationship with Spike, and highly doubtful Spike would have thought of the issue at all. And Angel, by the time he started getting tentatively involved with Cordelia, was planning to become human again anyway.
 * The initial age problem was enhanced by Buffy being a high school teen; Buffy/Spike and Angel/Cordelia had slightly more adult girls. Buffy provides another variant: given probable Slayer life expectancy (a few years, cut short by violence) even an ordinary human romance could be Mayfly December, at least on average.
 * Also, given the fact that Angel was fighting side-by-side with Buffy, his survival chances weren't much higher. It would have been entirely plausible for him to die in battle, leaving Buffy alive.
 * It should also be noted that by the time Angel starts getting involved with Cordelia.
 * It should also be noted that the life expectancy of each character, in terms of their relationship, was rarely brought up. Angel's stated reason for leaving Buffy was that his curse (making him unable to ever be truly happy with her, which obviously would put a strain on both of them) and his nature as a vampire (sterile and lethal reaction to sunlight basically rules out any kind of normal family situation) made him unable to give her the life she deserved.
 * Played with for Anya/Xander. They never had a Mayfly-December Romance relationship, but only because Anya lost her immortality for the duration of their relationship, and got it back after they broke up. Notable in that she lost her immortality in an unrelated fight with Giles, and got it back only because she was so furious about the break up.
 * Their potential difference in lifespan has been a source of angst to Superman and Lois Lane in various incarnations. In particular, an episode of Lois and Clark focused on it, with Clark admitting he had no idea how fast he would age—if he aged at all. It was possibly resolved when Superman gave up some of his youth to rescue Jimmy from Rapid Aging and also to de-age the villain of the day into a baby, and one of the characters suggested that Superman had given up enough of his youth for it to no longer be an issue. Of course, since the show didn't run that long, we have no idea if Lois still has to worry about this...
 * Partly averted in New Amsterdam, where the premise is that the main character will be immortal until he finds and weds his true love. Only partly averted, because any relationship with someone other than his true love would fall into this trope, including platonic relationships such as his 67 children. He has mentioned being careful to avoid siring more children specifically because of not wanting to watch them grow old and die before him.
 * It hasn't been addressed in the actual show yet, but Word of God states that Chuck from  Pushing Daisies, having been brought back to life by her childhood sweetheart Ned, will now not age, while he will. Add that to the fact that they can't touch and you have a relationship more fraught with obstacles then the one between Romeo and Juliet.
 * All of Jack's relationships in Torchwood. Unless we're counting The Doctor, of course. But whom are we kidding? He's never around.
 * According to a photograph seen briefly at the end of "Something Borrowed"
 * In "Small Worlds", we see Estelle, an old woman who tells Gwen about how she was in love with Jack's father decades before; turns out it was Jack, and the affection is still obviously there on his end despite his being, physically, several decades younger. His reaction to  at the end of the episode was heartbreaking.
 * Children of Earth: "Day One" introduces us to Alice
 * It's been addressed now, in the radio play The Dead Line.


 * Also addressed in a conversation in Children of Earth, Day Three. And then, of course,.
 * In the last two episodes of the first series of Being Human (UK), vampire Mitchell runs into an old flame of his, who is now a fairly old woman..
 * On Heroes, Sylar seems to believe that this inevitability is grounds enough upon which he can begin to build a relationship of some sorts with Claire. Despite the fact that, at present, she's not even eighteen where he's roughly thirty—and that he's a sociopathic murderer and she hates him with a fiery passion. He promises she'll get bored of trying to kill him one day...
 * Battlestar Galactica, Starbuck not only tries but actually succeeds in killing her unwanted Cylon suitor. He keeps coming back anyway.
 * As with the film series, all Immortal/mortal relationships in the Highlander TV series are this. It's spotlighted in the season one episode "Studies in Light", in which Duncan encounters a mortal woman who was his lover fifty years ago.

Machinima

 * The film "May Flowers" made with The Movies features a romance between a normal human man and a woman (the titular character) who is an ancient species, timeless but not ageless. Over the course of a year she ages an entire lifetime and dies at midnight every New Year's Eve only to be reborn as a baby seconds later. May finds husbands to take care of her during this time but does not stay married to them for more than 50 years.

Music

 * This was the theme of the music video for Paula Cole's big hit "I Don't Want to Wait," an immortal woman who had lovers in several time periods who each died.
 * The song "Puff The Magic Dragon" describes a Mayfly-December friendship between the dragon and his best friend in its final verse. It breaks the dragon's heart (as well as its listeners').
 * As with the Toy Story examples above, the issue is that he and all his adventures "make way for other toys".
 * Sonata Arctica's song "Under Your Tree" describes this kind of friendship. Originally it was written because Tony Kakko's (main vocalist) dog, whom he raised since he was a pup, died, and the day he was born he planted a tree. Now many years later the only things left are the tree and the memories.
 * Josh Ritter's song "The Curse" depicts a relationship between a mummy who is blessed/cursed with immortality and the archaeologist who enters his tomb and "awakens" him.
 * Free Parking's "My Girlfriend is a Robot" pretty much sums up this dilemma in four minutes.

Tabletop Games

 * Half-subverted in Dungeons & Dragons. While half-elves tend to have somewhat downbeat childhoods, their parents can apparently have quite happy lives together; the human is attracted to the elf's grace, the elf to the human's energy. It's implied that the human gets a partner who doesn't age for the duration of their relationship, and the elf gets a satisfying if short-lived (for an elf) tryst without any worries about bad breakups (assuming their human partner dies of old age). Other half-races, though, either play it straight, tending to come about because of Mayfly-December Romances (half-dragons—even an elf will be in their grave for millennia by the time a dragon lover dies), or in the few exceptions avert it entirely. In the case of half-orcs, it's reversed, since orcs have far shorter lifespans than humans and are more likely to die by violence.
 * Actually actively averted in the Elves of Alfheim supplement for the Mystara campaign setting. Elven romantic relationships are not expected to be "for life" and it is rare that an elven couple doesn't drift apart after at most a century. Elves with human spouses don't like when they die, of course, but don't see this trope as a big problem.
 * This actually a very integral part of Vampire: The Masquerade. Part of what causes vampires to slowly turn more inhuman in attitude is the fact that any human relations a vampire has will eventually die. This either slowly drives them mad from despair, or they stop bothering with considering humans anything more than toys or lunch. Vampires who try to fight this dissolution of humanity tend to be unhappy.
 * Keeping ghouls (humans with vampire blood in their system) doesn't help, either. They don't age, but they tend to go insane for the same reason that vampires do (although slightly faster).
 * And if you try to go all the way and try to make your special someone a vampire like you, it's a crapshoot at best, with I Hate You, Vampire Dad prone to rearing its ugly head.
 * Warhammer Fantasy Battle has one: the Vampire Count Vlad von Carstein and his beloved wife Isabella. Of course, because this is Warhammer there is precious little angst over this as they are both bloodthirsty Complete Monsters of the old school, even before Isabella became a vampire.

Video Games
"Asari: Well, you have to appreciate the time that you DO have with the fish- Turian: Oh, this is the lifespan talk, isn't it! We're not having the lifespan talk! Asari: We have to talk about it some time!"
 * In Lunar: Eternal Blue You find that
 * Presumably this will be an issue for Lucia and Hiro as well.
 * Inverted with Fire Emblem's quasi-canon couple Eliwood and Ninian. You'd think being a
 * Which leads into the relationship between Eliwood's son, Roy and possible bride Sophia  It should be noted that the support conversations between   Sophia and   Fa also directly discuss this trope, albeit from the friendship angle.
 * In the same series, there's also Sothe and Micaiah. It can be assumed that Micaiah, being Branded, will live much longer than Sothe. This is the reason why the two weren't together during Path of Radiance, but the topic isn't addressed much in Radiant Dawn.
 * Ike and Soren have the same problem. Remember that  was one of only two living people to have personally met the goddess.
 * A point that's brought up by both Nono and Tiki in Fire Emblem: Awakening if they form a relationship with Richt and the player's character respectively, as both of them are are Manaketes and capable of living for thousands of years. Nono questions Richt about whether he really wants to marry her when she'd be looking youthful as ever even when he's an old man, while Tiki states that she's aware that she'll have to part with the player long before her life ends, but promises she'll remember him forever.
 * In Mass Effect, the prolonged lifespan of the asari has colored their relationships with most of the other species, along with their ability to mate with anything. Liara explains that asari who enter into physical and emotional relationships with members of other species do so fully aware that they will outlive their partners, and take a "long view" of the relationship.
 * The children from such a relationship are always asari. In fact, most asari are the products of such relationships, as there is a stigma attached to being a "pureblood".
 * This isn't so bad if the partner is a human or turian, who live, on average, to the age of 150; with krogan, who have a similar lifespan to asari, it's not even an issue. Salarians, meanwhile, are lucky if they reach 40 - because asari are so long-lived, salarian parents won't even see their children reach adulthood. This is perfectly illustrated by a elderly 35 year old salarian and his 60 year old teenage asari stepdaughter in the second game.
 * One asari mentions this as a reason she's hesitant to get it on with a krogan. Krogan have at least as long of a lifespan - there's mention of one having "millennia" of experience - as asari, making it a big commitment. With humans "you just stick it out a century, and they die".
 * In one particular mission you have to get a fish for a Krogan at the Citadel. In the shop, you can hear a Turian and Asari talking about getting a fish, and the Turian said that maybe they shouldn't get a fish because they only live for a few years. This is pretty much what happens.

"Good Dwarf: I'll still love you when you're spoiling your grandchildren, and when they're spoiling theirs."
 * Another possible example is the relationship between Commander Shepard and Thane Krios. One of the first things that Thane tells Shepard is that he is dying of a deadly disease and has only months to live. The fact that Shepard/the player can choose to pursue this relationship anyway, fully aware of this, puts it in this category.
 * On the other hand, it is possible that the third game may have something to say about Thane's fate.
 * Liara herself is an example of this. She is very young for an asari, but even so, Shepard will most likely only be around for around the same time as she has lived thus far. This is the asari equivalent of getting married at 20 and one partner dying at 40, while the other lives to be 150, or more like comparing the lifespan of a dog to a human.
 * In Lair of the Shadow Broker, she'll even mention she's only just about to turn a 109 (and typically, asari can live up to a 1000 years). Won't stop a faithful Shepard from proposing a Babies Ever After ending.
 * The main relationship in Metal Gear Solid 4 is a platonic Mayfly-December love between two best friends, one a normal man approaching middle age, and one a clone with rapidly-accelerated ageing which has left him physically seventy while being only about forty-three years old.
 * Played straight, averted, AND subverted in Lost Odyssey: Kaim, Seth , Ming . The immortals' , and it is shown that, even if they learn to live with the death of their loved one, the immortals still suffer from this, sometimes even.
 * In the Myst series, Katran has, it appears, a normal life span. However, her husband Atrus is one quarter D'ni, They were close in age.
 * This is kind of subverted in another background novel, The Book of Ti'Ana- the lifespan discrepancy between the human Anna and the D'ni Aitrus is one of the reasons their marriage is opposed, yet the couple themselves are less bothered by the issue. However,.
 * Fridge Logic implies this with the Official Couple of Tsukihime.
 * Though not a romantic relationship, this is strongly hinted at in Tales of Symphonia, where expresses sadness that he will greatly outlive his human True Companions.
 * Also, you have the option to pair off Lloyd with the Raine, or the  Presea, both of whom will outlive him.
 * Has everybody suddenly forgotten Kratos? He's, and his wife was.
 * In the sequel,
 * Did you forgot that Lloyd's.
 * Also prominent in Tales of Phantasia, with the half-elf Arche. Even though she's from one-hundred and two years in the past, she's going to live much longer than all of her friends, and even her love interest. It's shown in one of the sequels
 * Again, not a romance but touched on in Touhou. Sakuya explicitly refuses to become immortal and serve Remilia forever when given the opportunity, although promises to serve her until death.
 * Yukari's friendship with Yuyuko was almost this, with Yukari being absurdly old even back then and Yuyuko being human. However, after Yukari fooled around with Yuyuko's border of life they have continued their friendship for almost a millennium so far.
 * Mokou will outlive everyone but her rival Kaguya, including Keine, one of her extremely few close friends, resulting in her basically living as a hermit to avoid relationships. Kaguya herself isn't bothered by this though, both being far more self-centered and living with Eirin, who is ancient even by Gensoukyou standards.
 * There is much fanmade material on the subject:
 * The Song of a Broken Youkai who Loved a Human
 * An Alice x Reimu video set to "Thank You, My Twilight" by The Pillows.
 * Many doujin, such as GERANIUM by Can't_Fix_the_Helmet, which features an aged Marisa and Kourin.
 * In many Harvest Moon games, your character has the option to marry the Harvest Goddess, and occasionally, other supernatural figures. (In More Friends of Mineral Town, you can marry a Kappa, and in DS, you can marry a princess who's Really Seven Hundred Years Old.) While the Harvest Goddess is generally a fairly distant wife (she mostly lives in her designated spring), she's still happy to see you when you come around.
 * There's also various incarnations of the Witch Princess in several games, who's a witch, acts like a princess, and is Really Seven Hundred Years Old. Animal Parade introduced male versions of the Witch Princess and the Harvest Goddess—the Wizard (no word on whether he's a prince or not) and the Harvest King.
 * "Old Man" Andrew, a supporting character from Mega Man Zero had this as a part of his backstory. He was a Reploid, she was a human, when she started aging he at one point had himself converted to look old, guess the mind must've followed suit because all he does nowadays is be by himself reminiscing.
 * Avoided in the backstory of Suikoden 3, where it is revealed that gave up  the source of his immortality, to be with his lover . Played straight with, whose  grants him immortality, and is revealed to be the father of
 * Nash and the vampiress Sierra. They do have the option of turning him into a vampire and who knows, maybe they already did. At the very least, he has stated that he wouldn't mind spending an eternity as vampire with her.
 * Played straight in Avalon Code, where . If the male player character chooses Georg's daughter Sylphy as a love interest, it can be assumed this trope would apply to their relationship as well, albeit not in-game.
 * In Embric of Wulfhammer's Castle, the Duchess can have this sort of relationship with the Good Dward and.
 * Avoided in the backstory of Suikoden 3, where it is revealed that gave up  the source of his immortality, to be with his lover . Played straight with, whose  grants him immortality, and is revealed to be the father of
 * Nash and the vampiress Sierra. They do have the option of turning him into a vampire and who knows, maybe they already did. At the very least, he has stated that he wouldn't mind spending an eternity as vampire with her.
 * Played straight in Avalon Code, where . If the male player character chooses Georg's daughter Sylphy as a love interest, it can be assumed this trope would apply to their relationship as well, albeit not in-game.
 * In Embric of Wulfhammer's Castle, the Duchess can have this sort of relationship with the Good Dward and.


 * Hatoful Boyfriend, a Dating Sim where the human female protagonist dates pigeons, brings up the lifespan differences between humans and birds a couple of times, especially during Ryouta's route where he points out that he'd die much sooner than Hiyoko and that he doesn't want her to go through the pain of losing a loved one so early like he did with his mother.
 * In Katawa Shoujo, Hisao expects to die young from his heart condition, while none of his potential girlfriends have conditions that limit their lifespan.
 * In Xenoblade Chronicles, the High Entia live about five times longer then the Homs do, but they have a longstanding tradition of having a human consort in their royal family. The same goes for the half breeds that have resulted from such unions, and you help one get together with her Homs boyfriend on a particular quest. They never really seem concerned by the differences in their longevity in either case, though.

Web Comics
"Edward: What...How...This isn't right! Immortal/Mortal romance is supposed to be angsty and star-cross'd and drama-ACK cough cough *gargle* choke wheeeeze..."
 * In the semi-revisionist fantasy web comic Errant Story, it was fashionable for some time in the past for the immortal elves to take on human lovers, so that they can experience the mourning, sad joy of seeing their lover grow old and die (especially since relationships between two immortal elves inevitably resulted in the two getting bored with each other over the decades or centuries); apparently this was their culture's take on mono no aware. Elves, in this story, have a lot in common linguistically and culturally with Japan.
 * Vampire sorcerer Pat in Sorcery 101 had one such marriage in his (un)life, since he submitted to being turned to keep his wife from being killed, and has since been avoiding his only real friend because of the situation. He's in the midst of searching out the spellbooks of an ancient sorcerer who he is convinced found a magical cure for vampirism. Danny, his student (and the main character of the comic), is likely to end up in a similar situation eventually because he has a blood bond with another vampire, Seth, meaning he's stuck at his current age, health, and body shape until Seth dies. Given that Seth has lived 2000 years so far and is too much of a bastard to stop, Danny's got a long life ahead of him.
 * In Tales of the Questor, Elves grow to full maturity in approximately 20 years--- then die shortly afterwords. One of the main characters is Sam, a fourteen-year-old half-elf, destined (unless a Deus Ex Machina intervenes) to die in her mid thirties. The reader may draw their own conclusions as to what this meant for her parents, and what it will mean for her.
 * In addition Raconnans are supposed to have a lifespan of 250 years, and the author once stated that May–December Romances are fairly common among them due to their long lifespans.
 * Spoofed in Girls Next Door, when a certain wangsty sparklepire discovers that not only is his new mouthbreathing target (Sara Williams) already staked out by another glittery, immortal object of fangirl lust, but that their (comically dysfunctional) relationship is entirely angst free. He does not take it well, and starts choking on his own Bishie Sparkle.

"Layla: Tough! Me and Kade are in it for the long run! Maria: The long long run? Your aging will slow down soon. He'll be in his 40s before you turn "19"."
 * In The Inexplicable Adventures of Bob,  gives this as one of several reasons she cannot pursue a relationship with , yet also the reason she is reluctant to leave Earth's solar system. "If I turn my head for a moment... he'll age to dust before I can look back." Shown here.
 * In the web comic Twokinds, the average lifespan of a keidran seems to be between 20 and 25. Trace (a human) briefly attempts to find a way to extend the life of his keidran lover Flora before giving up and deciding to make the most of the time they had.
 * In Eerie Cuties when Layla's relationship with her werecat boyfriend was revitalized, her mother tried a vampire version of "The Talk" to both spare her some pain and get Arranged Marriage back on the rails:


 * Girl Genius with Higgs/Zeetha, especially after it was hinted that he may well be a Jäger general, and as such a few centuries old.
 * Schlock Mercenary with Kathryn Flinders and… Karl Tagon. Yes, father of good old Captain Tagon. They met when Toughs were rescuing him and Kevyn-2, and she happened to be a driver, so [//www.schlockmercenary.com/2010-11-14 she was with her original looks and shooting mafia thugs, while he was a head in a jar]. Nothing special, beyond a mild compliment/leery comment for the sake of appearances. Then after more misadventures (and some cosmetic surgery) she [//www.schlockmercenary.com/2011-12-12 decided to travel with them], just for one trip. Then enlisted. Then she accidentally referred to Karl by his first name a few times. And one fine day Murtaugh bluntly told Karl exactly what is going on and why Kathryn invariably volunteers to work with him. Of course, that was after the indefinite life extension treatment became available.

Web Original

 * Discussed in a couple Cracked.com articles:
 * "7 Awesome Super Powers (Ruined by Science)", #1 Immortality.
 * The example from Fred Claus is one of the 6 Horrifying Implications of Classic Christmas Movies.
 * Played for Laughs in Mudy Quest, where Darkmoon (a drow) and Totenkopf (a gobbo) are 923 and 11, respectively. They are of comparable appearance, however; she ages slow (or is immortal), while he ages fast.

Western Animation

 * Completely ignored in Transformers, where romantic relationships between Transformers and human females are an uncommon but not completely rare occurrence. However, since Status Quo Is God, the relationships are never shown again after the initial episode and one might assume they've broken up again.
 * Gargoyles, when Goliath and Elisa finally hook up. Gargoyles age at half the rate humans do, so Goliath still has about 115–120 years left in him. A bit more mild than most examples, but still, he'll outlive her by decades.
 * Toyed with by the fandom in My Little Pony: Friendship Is Magic on two points. The first is the issue of Princess Mi Amore Cadenza, who may or may not be immortal, marrying a definite mortal. Second is Spike's Precocious Crush on Rarity, which has shades of this given that Dragons are supposed to have lifespans tremendously longer than ponies.
 * Toyed with by the fandom in My Little Pony: Friendship Is Magic on two points. The first is the issue of Princess Mi Amore Cadenza, who may or may not be immortal, marrying a definite mortal. Second is Spike's Precocious Crush on Rarity, which has shades of this given that Dragons are supposed to have lifespans tremendously longer than ponies.

Real Life

 * George Francis, a black man who, at 112 years old, was the oldest man in the U.S. until his death in December 2008. He was born in 1896, a mere 30-odd years after slavery ended... and he lived to see both world wars, the civil rights movement, and the election of Barack Obama. He saw the beginnings of the telephone, automobile, airplane, computer, television, the internet, space shuttles, cell phones, and all the other things we see as mundane. Even in old age, he maintained his lifelong interest in politics, voting for Obama in 2008. His family called him the man of three centuries. He was survived by 4 children, 18 grandchildren, 33 great-grandchildren, and 16 great-great-grandchildren. His oldest son, Anthony Francis, is 81. And his wife, Josephine Johnson Francis, you might ask? She died of cancer in 1964, half her husband's lifetime ago. This whole scenario may seem too far-fetched to be true, yet it is... a true Mayfly-December Romance.
 * Johannes Heesters, Dutch stage and film actor, who was at the time of his death in 2011 at age 108 the oldest actor still working, once mentioned that the only thing he was afraid of was that his wife (who is 43 years younger) might die before him.
 * Well, he doesn't have to worry anymore.
 * Any Real Life romance in which one of the participants is terminally ill, and both are aware of this fact, sadly contains elements of this trope.
 * So do humans' relationships with most species of pet, for that matter.
 * Per Long for This World, Aubrey de Grey and his wife Adelaide Carpenter are potentially a literal example: Aubrey is a gerontologist who plans to live forever, while Adelaide has "no interest in immortality."
 * Many animals, particularly insects, have large differences in life expectancies between sexes.