D..
It's not a "shallow note", mentioning that you've only been with him. It's a really important one. You have absolutely noone to compare him to, or a relationship with anyone who is not abusive. You think that if he could have a girlfriend, that maybe he has changed. You are WRONG. He's waiting for later on when he has her convinced that she loves him so that he can treat her the same way he treated you. He has learned NOTHING. You don't seem to understand that people don't stop verbally abusing their loved ones just because they promise that they won't.
What makes you think that he'd be faithful to you if you did move back in with him? He has a girlfriend. Why would he give that up?
You need to stop pining after this abusive man and get into THERAPY and learn how to prevent yourself from picking the same kind of loser the next time around. There are PLENTY of men out there who aren't abusive. If you think that you couldn't find one of them, then you really have a self-confidence problem and you need to remedy that for LOTS of reasons.