Talk with your girlfriend. It seems like he won't fight her, will he? I mean, come on. If she gave a crap, she' d talk some sense into him before hand. If that doesn't work, its time to do some research on what his vulnerabilities are. Find out his weaknesses and exploit them. Dont go too far, hurting him further won't help you any. But you should start to build alliances with people that care about him and don't want to see him arrested, tried and sent to prison for assault. The loss of his future should out-weight the few minutes of joy he'd get from beating your ass. He needs to know this. Then if he still wants a piece of you, fight him. Just him. Don't get anyone else involved. Don't back down, don't run. Pain is only temporary. Bruises heal. Being a coward stays with you forever. Count on a fight, and prepare for it however you want. Then IF he doesn't fight you, its a win- win for everyone. Move on...