You are a parent first and an LBS second -- do what is best for your kids. One suggestion would be for you and W to meet with a family therapist, discuss the situation, and get some tips on the best way to handle it for your kids. That way it's an independent authority, not you condemning W for her actions.

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