B.I.L.B.: Stealing best friends' girl/boyfriends

I think that it isn't good to steal your best friend's boy/girlfriend, since friends are for your whole life and boy/girlfriends not. I don't think that it's worth risking their friendship for a boy or a girl. In the movie, I don't think so, because Jules is not going out with Joe, she only says that she likes him. That does not give her the right to reproach anything to her friend.

Patricia