Hi Wahine, apart from the kids, what is holding you there? Just wondering if it's financial barriers, or you're afraid of the future, or parenting alone? There might be a way of you staying in the same house, at least for a while, because you have children.
The usual advice is to keep a diary of when he's drunk, when he drives drunk, and anything significant about his parenting, or the way he acts towards you (verbal abuse, financial abuse etc.).
I would worry about the affect of his behaviour on the kids. The drink driving is no example for youngsters to see. Is there any chance of you getting him arrested when he drives drunk, anonymously if you're afraid of him?