Let him know that you will not tolerate this behavior. Go to the police, leave him, do anything to show him that you are serious. If he brags about hurting someone, this should be a warning signal for you. This makes him potentially dangerous and you a potential victim. Finding a parking space, or when he can't get the stereo to work, etc.
Control is the biggest issue in battery.
It can be either overt or subtle. Overt is bullying, dominating, and is often maintained by threats. Trying to control the way you dress, what you eat, how you spend your money, who you see, etc. Subtle is when he oversees your life in a seemingly kind and caring way. Driving you everywhere, lending you money, filling out forms.