I would be glad he's the one getting to deal with the alcoholic crazy train and not you. I know it's not that easy, but you're really getting the better end of the deal here. Relationships coming to an end are never easy and there's always a recovery period afterwards. Are you going to Al-Anon? If not, you probably should.
As for kids, having been a single mother for a while, I can say that kids should never be brought in unless you're pretty serious about the person. I wouldn't let anyone meet my kids. My husband met them kind of early on accident, but I knew in my heart he was the one. His kids, on the other hand, live with their mother, who is on her third live-in bf in as many years. Those kids are so confused about how families and relationships work. It's really sad.