Mono-we must have been typing at the same time.
I feel the same way as your ex-wife. The only clarification being-that I could/can handle that continuing... (the "other woman").
It used to really bother Maca when I said I wouldn't leave him if he had a relationship with another woman, but it was the truth.
Ironically-part of why I DIDN'T tell him the "whole truth" much of the time, was because of that exact thing-when I told him that it hurt and upset him. I didn't understand WHY and I didn't want to hurt and upset him by saying something that need not be said (NOT saying that is why I had an affair, I'm talking about OTHER not said things I felt or thought).
I think you are dead on about "mistake" or not. My 1st Sgt in ROTC used to say (all the time) "If you walk into a walk, that's an accident-if you do it twice that's stupidity." Same sort of concept.
RP-I think it's KEY for EVERYONE to understand that there is a NEED to continue our "education" throughout our lives. If that concept is natural for every person, then person A making a mistake knows that they need to work on learning from their mistake and person B (who was hurt by the mistake) knows that they need to allow person A to grow and learn from their mistake as well....
(not saying HOW one allows that, just saying)....