If you had no children and if she didn't go out on you balanced slate if you will, would you still be interested in her? and why?
Do you have a belief system that makes you resist splitting up?
Now add back the children, the In-laws and the infidelity, and ask the same question but with a twist. "If you were the one that she came to as the "other male" would you be interested in her with her "baggage"?
Pity me that the heart is slow to learn
What the swift mind beholds at every turn.
Edna St. Vincent Millay