Something else you need to know, hexx, is that alcoholism and abuse are two completely separate problems. Even if he became more violent when he drank, the power and control that lie at the bottom of abusive relationships is something that exists separate and apart from the drinking. Getting him sober wouldn't keep you safe--not reliably so, and it wouldn't prevent him from nursing grudges and undermining you in subtle ways in an attempt to control you.
In short, even when he's not drinking, he poses a threat to you.
I got an email today from someone I used to work with, about a case one of my former colleagues tried a few months ago. A young teenaged girl was shot in the face by her father, who then tried unsuccessfully to shoot the girl's stepfather. She is paralyzed for life. Domestic violence ends in tragedy so often.