You need to take the focus off your h and put it on yourself. He is so alien to you right now that he is on the mother ship. You need to be both parents to your children. You need to spend the time with them that he is not. You need to do things for yourself. You need to stay healthy physically and mentally. Let your h twist in the wind. There is nothing you can do for him. There is nothing you can do about how many relationships he destroys with his family.
This won't be easy and it will take a long time for you h to come through this. He is on a journey and you are not invited. You must go on your own journey. Take this time to grow and work on yourself.
Come here as often as you need. There is a lot of amazing people with valuable insight.