How can you possibly want your children to grow up with a violent drunk in their lives, though? OK, you missed having a dad when you were young, but a man like that is not a dad either. He's... did I already say violent drunk? If he's good with the children when he's sober then, as PotPourri says, he can be good with them during access times, which can be as generous as you want. But I can't see that being under the same roof with a you-know-what is really a good option.
As an aside, I do sometimes wonder when women say "I couldn't do that to the kids", whether it's an excuse that saves them having to make a difficult decision. Because leaving a marriage is hard, make no mistake - though sometimes it's so bad that not leaving it is harder. But they don't have to think about it because there is this one great obstacle to doing anything at all: Not Taking The Children Away From Their Dad. Then they can feel all noble next time they've been kicked down the stairs, because it's all for the kiddies. It sounds like I despise such women - believe me that's not the case - it's the attitude of mind I despise, and the situations that force us into it. I've done my share of denial, in marriage and in other situations too (though XH was never violent), looking for any excuse not to have to think about an issue today or tomorrow, maybe some time next week, or in 15 years' time when the children leave school... Think about it now, I say, look at what is really happening. This is not your childhood that you're having a chance to relive, this time choosing to keep your father around; it's a different situation, different man and different children (yours! They're not you, but they are your responsibility) and it's BAD.
I know Attila will be on shortly to remind you that children learn about relationships from their parents, and that learning to be beaten by an alcoholic is not really what you want for your daughter in years to come, surely?