When do you walk away? Now sounds like a good time. You don't have to put up with physical aggression. You children certainly do not need to be exposed to that. Fear of the unknown is not any reason to stay in such a situation. Do you work? Do you have family nearby? Do you have friends who could help you? Do you have a church family that could help? There are many, many ways out. A call to the domestic violence hotline would be a huge help. You don't have to do anything other than talk to them. They can direct you to places where you can get help for yourself and your children.
I'm so sorry you are dealing with this awful situation. You cannot control his drinking or anything else, but you can control your own and your children's situation. Your husband's recovery (or lack of) is his own. You being there makes not one iota of difference. It just keeps you and your children in the middle of the chaos. Please, make the call.