If you're gonna break up, then break up. If you're gonna be "friends with benefits" then be that....either way, you have no "claim" on her and she has no "claim" on you....so if she is involved with someone else, so what! If you want her for yourself then tell her.
My foot missed my mouth ! Dang !
Fight Club. I'd tell you about it, but the first rule is that we can't talk about Fight Club.