Are people really that desperate to make move on a girl who already has a boyfriend?
I mean, why?
It will be one thing if they are unhappy with their relationship, but both are coping just fine with their own way of doing it. I doubt anyone would be dumb enough to make a move on a girl who is happy with their boyfriend unless you're some sick rapist bastard with a fetish to cuckold someone. I don't see why characters like them supposed to exist for?