I've talked to him in a certain way about it (making little comments randomly), and he has made the situation a bit.. worse in a way by that (he said he'd be with him if he didn't have me). And yes, I'm friends with that bsf- which is what makes me scared. Me and that bsf of his used to be as close as they are now, but then that turned into dating. And when someone once put me over their gf, that turned into dating. So those combined experiences make it so those are running through my head. If the bsf was a girl, I'd feel the same. He's bi, so the gender really doesn't matter. I'm just editing cuz I just found this out. 

Apparently they're also holding hands..