D, Grace has given you excellent advice. Leave the situation alone. The more you talk about the ow or attempt to show him the error of his ways, the more you will push them together. In their eyes, they are soulmates, your h has rewritten history and she's eases his woes because he's had such a difficult life. Not!
It's all about him and there is something deep within him that has never fully matured. He was emotionally stunted as a young kid/teen and now he's having to grow up after the body has matured.
It's a difficult journey, but you need to keep the focus on you and your children and finances. There is absolutely nothing you can do to turn him around. He must complete the entier journey in order to grow up completely. If it wasn't this ow, it would be another one. To them, it's who ever can ease their pain.
Pull your bootstraps up and fasten your seat belt...it's a long and winding ride, but I know you can do this!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.