Hi wantinhope,
Sorry you needed to search out this forum but glad that you did. There are many helpful and compassionate people here.
Just want to say, go with your gut, not your heart. How long were you separated before he hooked up with someone? Did he even stop drinking? I'm sure from what you wrote that you don't really believe this would end anyway, even if you gave him another chance. He's playing you.
Once you are divorced, make sure that the state monitors the child support. Do not agree to let him send it to you. He's already behind.
Hugs