If he really loves you, he would NEVER put his hands on you when he's angry.
I know that it's hard to break away from an abusive situation, especially when you feel that you love the person, but answer me this...is love supposed to cause you harm? No, it's not.
Maybe you should think of getting into a counseling program, and having your partner enter an anger management class.
You also say that you have a child....don't let your child see his dad(?) laying his hands on you. And don't let your child see mommy be a victim.
I know that you want what's best for your child, and getting him away from an abusive home is the best thing for him right now. Things may work out for the best in the future, but for now...you need to put yourself and your son out of harms way.
Good luck to you and yours=D