Fidelity Test

"Oh what makes you blush at so silly a thing? I thought to have had your golden ring; 'Twas I that robbed you all on the plain, So here's your watch, here's your watch and your gold again."

"Oh I did intend and it was to know If that you were me true love or no. So now I have a contented mind My heart and all my heart and all my dear is thine."

- The Female Highwayman

Alice and Bob are married, engaged, or otherwise attached. Alice gets it into her head to somehow 'test' whether Bob is faithful to her. Sometimes, she believes he is, but makes a wager with someone who insists that he isn't, or that no one else ever is. Alternately, she's just a suspicious bitch.

Then Alice's agent, or the person with whom Alice made the wager, or Alice herself in disguise, goes and attempts to seduce Bob. In almost all cases, Bob will prove to be true to Alice. Often she doesn't realize it, though; either her agent lies to her, or, in a twist as old as the trope, he sees through her disguise or otherwise becomes privy to her plan, and plays along to teach her a lesson.

A Sub-Trope of Secret Test of Character.

Anime and Manga

 * In Urusei Yatsura chapter 25, Lum went to Ataru's classroom disguised as a normal human. She didn't really intend it as a fidelity test (by this point, it's pretty obvious that Ataru would fail), but rather to see whether Mendō's suggestion that Ataru "prefers a girl as ordinary as himself" was true. However, she got upset at Ataru when he told Mendō that "Lum's yours [now]", so she (while in disguise) asked Ataru to promise to be faithful, and when he did, she dropped the disguise and told him "I will hold you to that!"

Advertising

 * There's a commercial (based on a very old joke) where a groom in a tux is propositioned by his fiancee's sister. He runs out the door and gets to the car, when his father-in-law-to-be and a group of other people tell him he passed the test.

Comic Books

 * Superman manages to do this accidentally to Lois Lane. After Clark and Lois have become a couple, but before he tells her that he's Superman, he forgets himself and asks Lois to dinner while still disguised as Superman, only for her to snap at him, reminding him that she's Clark's girlfriend.

Fanfic
"Green Arrow I: He's not exaggerating, Connor. I watched him do a bad Chippendale's impression, and Dinah was getting excited. Something's off here. Go, teach him how to ignore women's come-ons. * mutters* Lord knows you're the only one here who can manage it."
 * During the Olympics Plot of Jla Watchtower/DCNation, Roy Harper challenged the Greek Gods for a chance to resurrect Donna Troy. As part of the test, Aphrodite demanded he remain celibate from the time of the challenge until the actual games. For an Arrow, that was already easier said then done. And then, Aphrodite casts a spell that makes women fall head over heels in lust for him (with only Lian immune), leading to a memorable line out of Ollie...


 * In one Sailor Moon fanfic, Serena disguises herself as a hot supermodel and flirts with Darien, assuming he'll fend the false her off while proclaiming his love for the real her. It fails miserably, but only because Darien can tell it's her right away by looking at her eyes.

Film

 * In the film Extract, Joel is frustrated that his wife Suzie never wants to have sex, plus he's certain that the new temp is hitting on him. His friend Dean suggests that he set one of these up so that if Suzie is untrue, he can go ahead and have an affair guilt-free. Joel at first refuses, but later gets stoned and hires Brad to seduce his wife as the new pool boy. When he sobers up and realizes what he did, he tries to get in touch with Brad, only to find that he came a day early and already seduced Suzie (and he proceeds to come back numerous times after that, not being quite clear on the concept).
 * In the remake of The Thomas Crown Affair, Thomas deliberately makes it appear as though he's having a relationship on the side in order to try to find out if Catherine is just after the painting or not.

Literature

 * In For The Love Of Evil, when Parry is about to marry the lovely Jolie, a jealous suitor has a unicorn approach, hoping to prove that Jolie is not a virgin. Even her father is totally stunned when the unicorn allows Jolie to stroke it, proving her a virgin.
 * A libertine poem by Jean De La Fontaine is about a guy who thinks his wife cheats on her, and so pretends to go on a trip, repeatedly disguising himself as a merchant, a priest and a knight, and seducing her. She gives in every time, and when he confronts her, she says she cheated on him 3 times: with a merchant, a priest and a knight. He realizes she recognized him every time, and thus the Aesop is learned.
 * The novel Don Quixote has several smaller novels inside of itself, one of this "The Impertinent Curious", a married man decides to put to test his wife's loyalty through his friend, all goes well until his friend happens to fall in love with his wife and runs off with her after performing a perfectly excecuted theater making the man believe his wife is faithful. The man is eventualy commits suicide when he finds out that he was the responsible all along.
 * "Cephalus and Procris" in Ovid's Metamorphoses.

Live-Action TV

 * In the BBC sitcom Coupling, there's a business devoted to at least one half of this—setting up fake dates to test the fidelity of committed men. Sally claims that she has no idea of what they were supposed to do if the man stayed faithful.
 * The Dick Van Dyke Show has an episode where Rob wants to know how Laura would react to another man's advances. He calls her on the telephone using a fake accent, and is dismayed that she begins to flirt back. It should be noted that Laura knows right away that it's Rob on the phone.
 * In Drake and Josh, Josh is convinced that Drake's girlfriend is hitting on him, and sets up one of these with her and with Drake hiding and watching. She really had been hitting on him, but somehow knows Drake is watching and doesn't fall for the ploy.
 * In the Silk Stalkings episode "Red Flag", a company sends out attractive women to test the fidelity of men engaged to be married. They're usually hired by the families of the women to make sure the guy won't cheat on her after they're married.
 * In an episode of 3rd Rock from the Sun, August put tape over her nose and pretended it had been bitten off in order to test if Tommy would stay with her even without her looks.
 * In one episode of Get Smart, Max impersonates his exact double, King Charles to seduce 99. She realizes it's him and plays along, to his horror - until a fake phone call "proves" that the real Max has been at Control headquarters all day, to her horror. Naturally, at some point the real King Charles also turns up, and Hilarity Ensues.
 * One Monk episode began with a woman who was doing this getting discovered, then getting into a fight with the man that ended with her death.
 * On The Nanny there is an episode where Fran pretends to be an old friend of Max's who looks exactly like her to see if he is falling for her instead. He sees through it (but only after he notices the price tag hanging out of the back of her dress).
 * Most daytime talk shows (like Maury) will use this one on men suspected of cheating. The man will be put in the waiting room with a decoy who pretends to be another guest and comes onto the man, to see how he reacts. 99 times out of 100, the man will go for it, which gives the perfect opportunity for his girlfriend/wife (or the host) to throw it in his face when he says "I would never cheat on you!" The real comedy gold comes when the man attempts to defend himself, though most of the time they simply get mad about being set up.
 * Veronica Mars is hired by a neurotic girlfriend to test her boyfriend's commitment to her before he can propose, which involves setting up a "temptation scenario" that ends up starring Veronica herself.
 * In one episode of Hetty Wainthropp Investigates, while Hetty was busy with a case, Robert and Geoffrey decided to handle another case on their own, in which a man hired them to perform a fidelity test on his girlfriend. However, since Robert was too old and Geoffrey was too young, they hired someone else to do it.

Music

 * The Johnny Cash song "Frankie's Man, Johnny" is about a traveling musician named Johnny who has a girlfriend (Frankie) back home. One night during a performance he notices a very attractive redhead in the crowd and attempts to pick up on her after the show (while thinking that what Frankie doesn't know won't hurt her). His plan backfires, however, when the redhead slaps him and reveals that she is Frankie's sister. The experience scares Johnny straight and he never attempts to cheat on Frankie again.

Myth and Legend

 * The "Broken Token" ballads do this—their general pattern is "guy goes away for seven years and his wife/girlfriend promises to be faithful; she is propositioned by a stranger; she refuses; stranger reveals himself to be the original guy and as proof presents the other half of the ring/coin/necklace that she's been carrying around since he left".
 * Female example: the song "Sovay", in which a woman tests her lover by dressing as a highwayman and attempting to rob him of the ring she gave him.
 * Older Than Feudalism: In the Biblical Book of Numbers, there is a test for a woman suspected of infidelity, to prevent her jealous husband from going on a Roaring Rampage of Revenge without proof and/or from having her executed when it wasn't adultery but a big misunderstanding. The woman was taken to the Temple, and her head covering was removed while some grain was offered at the altar. Meanwhile, the priest wrote a curse on a piece of paper, and sprinkled dust from the floor into a container of water. If the woman was faithful, then the cursed water would have no effect on her whatsoever. If, however, she was cheating, the general interpretation is that the test would kill an adulterous woman—and, interestingly, her lover too, even though only the woman drinks it. (It's also worth noting that a woman could not be forced to take this test—before it's administered either she or her husband had the right to dissolve the marriage, rendering the procedure moot.)
 * In the Ramayana, Sita has been kidnapped and held hostage by Ravana, though she refused his sexual advances. Rama has her walk over fire to purify her...and rather than burning her, the fire does not so much as singe her, proving that she was, in fact, faithful to him. (Some versions have the flames turning into flowers as she walks over them.)
 * From Greek Mythology, the tragedy of Cephalus and his wife Procris has one of these. Cephalus was abducted by the goddess of dawn Eos during one of his hunting trips. Cephalus initially doesn't resist, since in Greek Myth it's usually impossible for men to resist goddesses, but he eventually starts pining for his wife. A disgruntled Eos returns him but spitefully insinuates that Procris had also taken other lovers in his absence. Cephalus decides to test his wife by disguising himself and offers Procris more and more money if she would sleep with him. The moment he sees her hesitate he reveals himself and calls her unfaithful. An ashamed Procris flees to become a follower of the hunt goddess Artemis, who calls out Cephalus for being a jerk. Husband and wife eventually reconcile and Procris even brings a couple of souvenirs like a magical spear that always hits its target.

Opera and Theatre

 * In Cymbeline by William Shakespeare, Posthumus makes a wager with Iachimo that his wife Imogen will be true to him. Iachimo fails to seduce her, but claims otherwise.
 * There's a Chinese opera whose plot runs thus: a poor man lands the luck of marrying a wealthy lady, and to raise his station in life he goes off to study for the Imperial Exams. Years later, he returns with a government post, and decides to test her faithfulness. Not only does she prove to be the iron lady, she gets quite pissed when he reveals himself and he has to beg for her forgiveness. (If I recall correctly, she lets him sweat for a while before doing so.)
 * In Cosi Fan Tutte, Ferrando and Guglielmo make a bet with Don Alfonso and he concocts the Zany Scheme in which they attempt to seduce their girlfriends disguised as Albanians.
 * In The Merchant of Venice, Portia and her servant test the fidelity of their newly-acquired husbands by demanding their wedding rings after saving the life of their friend, Antonio (it's complicated—there's drag involved). The men do fail the test, and the wives lord it over them for the rest of the play.
 * In Die Fledermaus, Rosalinde used the disguise version of the test on Eisenstein. He fell for it.

Webcomics

 * Relatively early in General Protection Fault, Ki tries to pull one on Nick. Using an old IRC handle she'd previously used to flirt anonymously with him. It fails, with Nick revealing to the audience that he knew who "Pookle" is.

Western Animation
"Bender: AHA! You love Flexo so much, you even love anyone pretending to be him! Angeline: Maybe I love you so much, I'd fall for you no matter who you're pretending to be! Bender: Oh, if only I could believe or even understand that!"
 * In Futurama, Bender becomes convinced that his girlfriend Angeline is cheating on him with Flexo (who is almost identical to Bender, if only it weren't for the beard). Bender disguises himself as Flexo and proceeds to seduce Angeline by acting exactly like Bender (or at least not like Flexo). After resisting for a long time, she gives in (as Flexo appears to be nothing like she'd thought): Bender triumphantly reveals himself, taking this as proof that she was cheating on him:


 * In the hit 80s show Jem and The Holograms, Jerrica is constantly worried about the fact that her boyfriend Rio is two-timing her with her holographic persona Jem. In one episode, she decides to test him by creating a third (holographic) persona - whom he instantly falls in love with. This proves to her that it's really her that he's loved the whole time.

Truth in Television

 * There are quite a few agencies that aim at seducing one's husband, in order to prove that he's unfaithful. Or capable of being so.
 * Whats funny about that actually using this trope in real life implies that half of the relationship has no trust in the other. Which means its already in trouble regardless of the result.
 * Which only proves true the quote, "Marriages don't fall apart because of infidelity. Infidelity is just a symptom of a larger problem."

Other

 * There's an old joke-cum-urban-legend that subverts this trope. A wife who disguises herself and follows her husband to a costume party. She seduces him as a Fidelity Test, but learns later that he gave his costume to someone else.
 * A joke goes that a man woke up one morning with a bad hangover. He discovered his robe had just been washed and ironed, and when he came downstairs, he found his wife had also washed his suit, put on a fresh pot of coffee, and was cooking a big breakfast. When he asked what was with the special treatment, the wife explained that he'd come home drunk at 3:00 am and passed out on the lawn, then soiled himself. To avoid the neighbours seeing, she dragged him inside and tried to get him out of his dirty clothes, but when she pulled off his trousers, he exclaimed "Piss off lady, I'm married!"