'''Basic Trope''': Someone loves someone else, but their love isn't returned--until they enter into another relationship.
* '''Straight''': Bob is in love with Alice, but she doesn't return his feelings. When he gets into a relationship with Carol, Alice falls for him.
* '''Exaggerated''': Every part of the LoveDodecahedron flips when someone enters a relationship.
* '''Downplayed''':
** Alice wasn't entirely oblivious before, but [[GreenEyedEpiphany once Bob and Carol become official she realises she's jealous]].
** Alice only acts on her feelings for Bob after he stops actively pursuing her.
* '''Justified''':
** Alice didn't realize she loved Bob until he wasn't on the table anymore.
** Alice liked Bob as a friend because he had a great personality but saw him as physically unattractive. But as it turns out [[SheCleansUpNicely Bob cleans up quite nicely]] and now she's all over him.
** Alice is the type of person who wants what she can't have.
** When Bob was pursuing Alice, she found him to be annoying, clingy, and possibly only being kind to her in hopes that she'd feel obligated to love him back. But once he starts going steady with Carol, he's more laid back, doesn't stalk Alice's every move, and his friendship feels more genuine. As a result, Alice starts liking him after all.
** When Bob realized Alice was a lost cause, he undergoes a personality shift, becoming someone Alice likes.
** Turns out Alice can be a bit [[{{Yandere}} crazy]] when in love, thus scaring Bob away.
* '''Inverted''':
** It's not until Bob's in a relationship with Carol that he realizes he loves Alice.
** Alice starts hating Bob when he doesn't hate her anymore and now hates someone else.
** Alice was Bob's UnknownRival. But Bob started to take their rivalry seriously around the time she got a new rival, making him her UnknownRival.
* '''Subverted''': Bob gets into a relationship with Carol. Alice is glad because that means he'll stop trying to pursue her.
** Bob severs all ties to Alice and uses SilentTreatment on her every time she tries to talk to him. Additionally, he never bothers with engaging with Carol, having decided that relationships are a tedious zero-sum game.
* '''Double Subverted''': But after a while, she realizes she secretly ''enjoyed'' being pursued…
* '''Parodied''': Alice openly and repeatedly mentions her vitriolic hatred for Bob--until he gets into a relationship, when those feelings are replaced with slavish devotion.
* '''Zig Zagged''': WillTheyOrWontThey.
* '''Averted''': Alice just plain isn't interested in Bob, before or after his new relationship, and is happy (and/or relieved) that he finally found someone.
* '''Enforced''': "OK, we've dragged out the UnresolvedSexualTension between these two enough, but how can… wait, I've got it! Let's have him get into a relationship with someone else!"
* '''Lampshaded''': "I know it's ridiculous, but now I can't have him… he's totally hot!"
* '''Invoked''': OperationJealousy: Bob starts hanging around with Carol in the hopes of getting Alice to see what she's missing.
* '''Exploited''': ???
* '''Defied''': Alice is well aware that Bob is only dating Carol to get back at her, and is disgusted that he'd use Carol that way, making Alice hate him even more.
* '''Discussed''': ???
* '''Conversed''': ???
* '''Deconstructed''':
** Bob realizes that Alice only started to like him once he was in a relationship with Carol, [[DoggedNiceGuy despite him pursuing her before]]. If it weren't for that, Alice might have never wanted to be with him. He is disgusted by this and cuts off all ties with Alice, who laments on losing a great guy.
** Because Bob spent most of his time pining for Alice, he didn't view Carol as a potential mate at first. As a result, their interactions are much more natural and they become friends, which slowly turns into romance. Their relationship is stronger than what he would have had with Alice because it's built on friendship rather than infatuation. With his romantic needs met, Bob no longer pursues Alice and now his interactions with ''her'' become more natural, and she realizes she likes the real him rather than the CasanovaWannabe he had been this whole time. In short, Bob is much more successful with women when he isn't trying ''way'' too hard.
** Alice rejected Bob in a particularly uncivil way the one time he voiced his affections, to the point that Bob would rather not acknowledge she exists. Alice choosing to make an advance when she knows he is with Carol only cements in Bob's mind that she doesn't really care about him, and never did.
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Back to UnrequitedLoveSwitcheroo. Funny, you didn't seem very interested in it until it started dating someone else…
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%% Optional items, added after Conversed, at your discretion:
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%%* '''Implied''': ???
%%* '''Deconstructed''': ???
%%* '''Reconstructed''': ???
%%* '''Played For Laughs''': ???
%%* '''Played For Drama''': ???