Take This Moment To Decide If We Meant It, If We Tried

So, a really (really really really) popular theme in slash fic is having one or both of the male characters be arguably straight, but their love for the other character is so intense that they are sexually attracted to them anyway, and thus hot male/male sexing ensues. I like this trope. It's a good way around writing characters who are canonically straight (or at least NOT canonically gay) into gay relationships, it fits in with the more modern ideas of mutable sexuality, and it's a lot of fun. I love reading stories Clark, or Kon, or Rodney, or Ted, or Harry, etc etc, is completely thrown for a loop by his feelings for another guy, when he realizes that all the while he's been fucking it up with women, he's had this serious, committed relationship that could have involved fantastic sex (and now will, yay).

But my brain is a mean, angst-loving plot bunny generator, and now I'm stuck on this plot for a fic where a character has to sit down and say, "you know what, you're incredible. You're gorgeous and funny and you make me happy, you've always been there for me and I'd do anything for you - but it's just not enough. It doesn't matter that I love you; I'm straight, and I can't change that, even if it means throwing away the best chance at a relationship I'll ever have." I want to write this soooo bad. But I don't have a fandom for it! It doesn't mesh that well with any of the pairings I ship really hard right now (McShep, Jack/Ianto, Cap/Ironman, Boostle, mostly), and it's not something that I think works half as well as original fiction.

Woe is me. This is going to be driving me crazy for weeks.