Am I Just a Toy to You?

Shuichi: Yuki... I know it's unlikely, but do you ever get jealous?
Yuki: Of course. You're my hole.

Shuichi: Bastard. I know you like my ass, but what about my heart?

—Gravitation manga

A situation common in works that aren't bound by No Hugging, No Kissing standards. Allison is being flirted with by Bruno in such a manner that it's unambiguously clear that he has an interest in her. This interest can range from playful teasing to kissing or even going all the way.

However, Bruno has a reputation as a Casanova or Handsome Lech with a penchant for going through girlfriends faster than a box of tissues, which makes Allison believe that he only views her as another Girl of the Week. This depresses Allison because she really does like Bruno, but dreads the inevitable day when he will grow tired of her and move on to a new conquest.

Eventually Allison will have to ask Bruno the titular question. Inevitably, the answer is no; Bruno's interest in Allison is more than sexual desire (which is implicitly shallow) and on a deeper emotional level.

Sometimes Bruno will be so used to Looking for Love In All the Wrong Places that he doesn't realize his deeper feelings for Allison at first, and will have to learn that there is a difference between lust and love.

Note that if Allison instead believes wholeheartedly that she's "different" to Bruno, Bruno will almost always live up to his womanizing reputation and leave her heartbroken.

Also see Sex Equals Love which sometimes overlaps with this, though the focus here is on whether the sex or flirting is motivated by love or not.

No real life examples, please; All The Tropes is not a gossip site.

Examples of Am I Just a Toy to You? include:

Anime and Manga

Early on in the Gravitation manga, Shuichi confronts Yuki on his sleeping around with women even after he's agreed to take Shuichi as his lover, demanding to know where he stands among all these women. Yuki replies that he's the first one... in stupidity, anyway. Later events prove that he really does care for Shuichi as more than a sex toy, though.
The hentai Strange Kind of Woman has an adorable almost-mute heroine who enjoys "collecting toys". Her new boyfriend is in the dark about whether he's just another toy or someone special to her. She won't say, being nearly mute, but towards the end of the anime she chooses him over her favorite vibrator, which ends up being crushed by a truck.
Berserk: Casca seems to imply this after she and Guts made love when he returned to aid the Hawks one year after he had left. He told her his plans of leaving again after their leader Griffith was rescued, which left Casca thinking of Guts as a selfish bastard who was ready to leave and forget about her in a pin drop. Then he told her to come with him. Cue in dumbfounded expression on Casca's part.
- This trope was then deconstructed and played for horror during the Eclipse when Casca is being horrifically raped by Griffith, and it is done so right in front of Guts. While Griffith, now as his demon alter ego Femto, is molesting and raping her in nearly every way possible, he is not actually looking at Casca at all - rather, he's staring at Guts THE ENTIRE TIME, as this horrible act was aimed at hurting Guts the most. After he's finished with Casca, he merely lets her drop to the ground as an exhausted and defeated woman.

Literature

A staple of romantic novels.
Loretta Chase's Mr. Impossible. Daphne thinks that Loveable Rogue Rupert's shameless come-ons to her are only his standard way of playing around with women. It isn't until near the end of the novel that Rupert realizes that love is the reason why his feelings for Daphne are more complex than wanting to get her naked, and is finally able to enter into an actual relationship with her.
In Heroes Adrift Lee finally gets sexually involved with her Urban Legend Love Life partner Taro. This scene is definitely likely to happen in the next book, seeing as she went into it expecting to get dumped when he finds other women to boink.
It's probably completely platonic, but something very similar to this trope happens in the Hand of Thrawn duology. Supreme Commander Pellaeon, hearing the rumors of his mentor and leader Grand Admiral Thrawn coming Back from the Dead, talks to a subordinate, trying to work out why Thrawn wouldn't have contacted him. He considers that maybe Thrawn just wants him where he is, out of the way.

Subordinate: I don't believe he would do that to you, sir. Not after all you went through together.
Pellaeon: You don't believe that any more than I do. Thrawn wasn't human, you know, no matter how human he might have looked. He was an alien, with alien thoughts and purposes and agendas. Perhaps I was never more to him than just one more tool he could use in reaching his goal.

Live-Action TV

In the Buffy episode "Hush," Anya complains that Xander doesn't have any strong feelings for her and believes the only thing he cares about is "lots of orgasms." She's proven wrong when Xander assaults Spike, believing him to be attacking her and drinking her blood.
- Spike also accuses Buffy of this once they start sleeping together. He is entirely correct.
In Spaced Twist asks Brian that she wants him to see her as a whole. When he assures her he does, she stresses "A whole Brian, with a w."
In the My Name Is Earl Flash Back episode "Guess Who's Coming Out of Joy," Joy has been cheating on Earl with Darnell. She suggests getting down in the freezer at the Crab Shack, which does not appeal to Darnell. He then asks her, "Why's it always gotta be just sex with us? I want to go to the movies, like a normal couple!" The two proceed to argue, and (temporarily) end their relationship.
In Gossip Girl, Blair wonders if the only reason Chuck has been pursuing her so tenaciously is because he can't stand losing. He confirms that it was all just a game to him. He's lying through his teeth.
A rare non-sexual use of a variant on the trope name, from The Nanny:

C.C. Babcock: You set me up didn't you? The run, the chase, getting stuck in the door... everything! My mental health is just a sick game to you, isn't it?
Niles: Rack'em up, let's play again.

Music

In the song "Paradise by the Dashboard Light", Phil Rizzuto's baseball play-by-play (which is also describing what's going on in the car between the two teens,) says

safe at third! Holy cow, stolen base!
He's taking a pretty big lead out there, almost
daring him to try and pick him off. The pitcher
glance over, winds up, and it's bunted, bunted
down the third base line, the suicide squeeze in on!
Here he comes, squeeze play, it's gonna be close,
here's the throw, there's the play at the plate,
holy cow, I think he's gonna make it!

- Which makes that a hell of a time to stop and have a relationship talk.
  - But one which makes him duly compliant in promising to love her 'til the end of time - and, in due course, praying for that very same end of time to be released from his promise.

Video Games

One of the most annoying parts of Metal Gear Solid 2 is Rose whining about this. Ironically, the reverse is true. She seduced Raiden as part of the Patriots' plans for him before Becoming the Mask.
Surprisingly, Hanako's path in Katawa Shoujo inverts this. Hanako allows Hisao to have sex with her because she doesn't want him to keep seeing her as a child that needs to be protected.
- Turns up in Emi Ibarazaki's path as well. Hisao thinks this may be the case, as she sleeps with Hisao multiple times, but doesn't want him to get closer to her emotionally. Thankfully, he realises her reasoning behind this and the pair eventually overcome their difficulties.

Web Comics

This xkcd.
In Magick Chicks Tiffany pointed out that Faith "loves" her... and half the school. Faith responds with what at the time looked like a deflection, but after what we have seen later, she most likely didn't even understand what was Tiff's deal, and took the comment at face value.

Web Original

After a date full of awkward small talk, The Nostalgia Critic screams this at the Chick, asking if she even cares about him before storming off. We find out later that he's one of the very few people who she does give a damn about.

Western Animation

Satan and Saddam in the South Park movie.