Hi, Unhappy. I'm sorry you're having such a tough time. I know how hard it can be living with someone who has an addiction. The undependability and garbage that goes along with it is crazy and yet they see nothing wrong with their behavior.
So if he's decided to be a father and husband - is he the husband you need and the father your children need? If he's not on either of those counts is he willing to make changes to meet his family's needs?
Only you know how you want your life and your children's lives to be. Keep focusing on yourself and your children and listen to your gut instincts. If you feel that something is wrong on any level then there IS something wrong. And that's ok - because once we realize something is wrong we have an opportunity to change it.