What should determine who's last name the baby gets? My sons father basically told me a few weeks ago he didn't want me living with him anymore and I'm not about to sit there and argue so I moved out.. Not even a week later he moved his friend and his friends girlfriend in and gave them what was suppose to be OUR SONS ROOM. So I'm super pissed about that. And I'm on the fence about giving our son his last name!!! Am I wrong for that???