My Best Friend's Love Interest
When your best friend and your lover get together, either by adultery or by the lover dumping you first.
It's very hard when your best friend and your lover get together. They're both precious to you, and you may well lose both of them at the same time, both from the trust-shattering betrayal and out of sheer jealousy. And friends and lovers can be hard to replace. May overlap with You Cheating Heart, but not necessarily: it's perfectly possible for your lover to leave you before consummating their romance with your friend. Needs a Better Description: mine is workable but kinda weak, and Needs More Examples, because it's been a long while since I've watched the sort of work where this comes up. Also Needs a Better Title, since this one sounds like a line.
- In Adventure Time, Finn The Human and Jake The Dog are super duper best friends, but Finn becomes friends with Jake's girlfriend, and Jake is afraid that something like this trope is going on, which rustles him badly.
Hello, Unknown Troper. You'll need to get known to lend a hand here.