Let's say you walked into a group of people in the dorm whom you don't know except a couple of people. After talking to them you notice that a cute girl is interested in you and trying to talk up to you, so much so that she is trying to talk instead of her boyfriend. So, long story short if a girl, who has a boyfriend, is interested in you should you try to approach her, and not to give a fuck about the boyfriend, or give up on her and try to make friends with her and her boyfriend(who seems to be a nice person)?

The place is very small and everybody knows each other.