Abusive Relationship

Okay, so I've been with my boyfriend for 7 months now and we have already been living together for 5 months. At first everything was great. But about a month after we moved in together my boyfriend started getting physically abusive. I have never cared about or loved anyone as much as him. Sometimes he is the most amazing guy in the world and other times he is the worst person I have ever met. I know this is probably stupid, but I still want to be with him but just the guy I knew the first 3 months of our relationship. I don't feel like I have anyone that I can actually talk to about this. I only have one friend that would understand what I'm going through but the problem is, she is married to his brother. I am so in love with him that I just want him to change. Tonight he informed me that he was talking to our roommate (his friend) and they had discussed moving out and leaving me to pay for everything on my own. I am not in a position where I would be able to do that and I don't have anyone else that could move in with me and help with bills. It is currently 2:00 a.m. and I am sitting in my car trying to figure out a way to stay warm and fall asleep because I have to wake up at 7:00 a.m. to get ready for a 13 hour shift at work. I guess at this point, I am just looking for some kind of advice on what I should do. I know most people will say to leave him but that it isn't exactly that simple.
Update: Thank you everyone for your advice. It really did help. I sat down and had a very long serious talk with him and surprisingly he has actually started to change. He has gone back to the person he was when we first started dating. He isn't going out and drinking anymore. If he does drink he only has 3 beers or less and he does it at home. One of our biggest problems was him drinking and driving. We are currently in the process of getting him legalized in the United States and if he gets in any trouble at all he is automatically out of the country. Every time he was abusive it was when he was drunk. Last time we went to the lawyer she suggested that he gave up all alcohol and I think him slowing down is his way of trying to do it. We do still have little arguments but he doesn't threaten to leave me anymore and he doesn't get physical. If things stay like this we should be completely fine.