Your sitch sort of reminds me of my own. My husband did a lot of "running away" in the marriage. He even filed for D a year before but put it on hold. Make sure your husband understands that you and the marriage are what they are and he has to accept it the way it is... both the positives and the negatives. Life can't always be rosy (not that you will not try, but life is full of ups and downs and people basically are who they are....). Also, remind him that the commitment is not just for your, but for the kids as well. He really cannot keep doing this to them. He has to make a commitment and stick to it. It's that simple.
The authors are Bettie Youngs Bilicki and Goetz. You can read more about it on Amazon.
There is no arriving, ever. It is all a continual becoming.