You know, I'm reading this thread and I don't have any back story yet but what's been posted and I'm going to tell you what I think, even though you are completely heart sick right now. You ready?
Yes doing you a favor. Yes, a huge favor. You need a man n not a God Damn project. He's a project. Let him go. This is not about you or anything you did. It's about him being able to drink without someone interfering. He won't get that with her because she'll be drinking with him. He can treat her like **** because she's just as vile n will fight him like a man. He can call her a who're n she won't bat an eye. She won't beg him to stay if he leaves for days on end because she's probably use to having men come n go.
You need to look your children in their precious faces and say to yourself, My child, you deserve more than what this man has given you and me. And go out and do it. When he calls you, do not answer. When he comes home, do not let him in. He left. He can stay gone. File for divorce and get some spousal support and child support. He has responsibilities that need met. If he wants to drink, he can go be a drunk but he needs to pay for those children.
I'm sorry you're hurt. But what a wonderful gift he's given you by leaving n taking his drink and ******** with him.