I read a book talking about how damaging your expectations can be. You can improve your situation by learning to drop your expectations of your wife. Instead, expect that she will never do anything differently than she does now. Assume she is not a caring mother and you will not be disappointed, instead you stand to be pleasantly surprised if she steps up.
Assume that the treatment you get now is the best you will ever get and make that your baseline expectation and you will be happier.
I, like you, felt that my wife was a wonderful caring parent. "The Captain" on the SSM forum suggested to me that a wonderful caring mother would not cheat on her husband and break up her family. That, by definition, makes her less than a wonderful or caring mother. The person you thought you knew so well is gone. Accept that and you're on the road to peace.
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015