There is nothing I can say that you don't already know or that hasn't been said by those wiser than myself. I'm just compelled to reach out with hugs and support though.
Right now, as you wrote, I don't think he sees that his choices jeopardize his family and a great M. You have *walked through fire* for this marriage and your family. He believes you always will. While that is what we strive for in a healthy R, he seems to be comfortable enough in that knowledge that he avoids making the changes he needs to make.
We know he's lucky ... you love him. Maybe he'll be lucky enough to find that you still do when he is strong enough to look at himself and face what he sees instead of running from it.
He has been hiding from/avoiding pain instead of going through it.
Growing is hard. Fixing mistakes is hard. Change is hard. In order to change, sometimes the pain of remaining the same must be greater than the pain of changing.
Sometimes the hardest thing and the right thing are the same.
He chose not to make a choice. You choose to protect the hearts of you and your children. If the man you love-- the man you need him to be--- is in there somewhere, he will fight to find himself, then fight to find his family, then fight to find you. I know you are afraid, mostly for him, that he won't be strong enough to fight. That's what makes you so very brave.