(((Vanilla))) In my opinion the only thing that you can do is move into your own place. Boyfriends, even husbands come and go, but your children are yours for life. This is an issue that your boyfriend has to deal with. This behavior didn't happen over night and if that's the way things have always been, you can't really fault the son. If your boyfriend refuses to deal with this you have your answer. Even though the son is totally in the wrong, you don't want to be in the position of son vs. girlfriend. If it's getting to the point that you are resenting your boyfriend and his son, then for your own mental health and the sake of your relationship, get your own place.