Anon: In the Web Original "Hat Quest" [[link http://tgchan.org/wiki/Hat_Quest]], the main character has two potential love interests, the girl he finds at the beginnning of the story and the one who starts out wanting him dead. The former is pretty much still in the running until just before he declares the latter to be his in Chapter 4, at which time this former girl pretty much flips.

Cut this quote down to the last two lines, sums up the trope without taking up so much space.

Well there's a rose in a fisted glove,
And the eagle flies with the dove
And if you can't be with the one you love
Honey, love the one you're with

Stephen Stills, "Love the One You're With"