Maybe, I'm technically not in this thread but I have a couple of questions for you, if you don't mind. On both sides of my family alcoholism is a big thing (not my parents, or me or anything, thank god), so I know a lot about this.
You say your hubs has a drinking problem. He hit your son on his arm, nothing too bad, but if he is so difficult and mean and horrible and abusive.. why are you with him?
Of course, you love him and of course a drinking problem is not alone a reason to leave someone because you want to help them. But as you are trying to conceive.. are you sure he is the right person for that?
I know it can be hard, trust me. But is your love for him enough reason to be with someone who will continue to hurt you and everyone in your family, as well as maybe your next child?
I'm in NO way saying that is the case.. I'm just nudging you to really think about this.
As, sweet as ever, JLM says, talk this through with your son AND your hubby when he isn't drunk.
O and yes, once they've crossed that line of throwing a punch, more will likely come.