Op when someone is good at turning things around and being manipulative to avoid accountability (which is what he's doing- he knows this is unacceptable he actually just doesn't care because he knows he can bully/manipulate you into forgiving him) the best thing you can do is look at his actions, not his words.
He's not just disappearing - he's going out getting hammered, spending family money, letting his kids down, leaving his partner in a vulnerable position, he's happily risking missing the birth of his child, he's obviously sleeping somewhere- with who would be my question and he's been presumably physically abusive to you in the past reading between the lines?
If you have a girl your relationship with this man will be her blueprint of what a healthy normal relationship is like. If you have a boy, this relationship with this man is what will teach him about women's place in the world and how to act in relationships. He is not a good father, your bar is just extremely low. A good father would never do these things and would never treat the mother of his child this way. You can't trust him, you can't rely on him and you can't talk to him about your worries and fears.
He has no reason to change op, he can take his money go out shag around and benefit from the family YOU do all the work for when he feels like playing family man. This all works in his favour which is why he's doing it. He's a narcissist. He KNOWS the impact on you and on the kids and he CHOOSES this because the most important person in his world, is him. Why would he change- he's got everything exactly as it suits him. It's not an accident. It's not a 'problem' he has. It's a choice.
This is what the rest of your life will look like right here op. Its not going to get better because men like this don't change. It will only get worse. Please, please do not waste the rest of your life on this waste of energy. You and your children deserve so much more.
I would recommend doing a freedom programme and speaking to womens aid because op - this is abuse. You are being abused. And you deserve support and much, much more. One person's love cannot support an entire relationship- it has to be two people equally invested and he's not.