W even told me "not to focus on the OM" because he's not the reason why she wants D. Our marriage was going to end with it without him
This is typical SCRIPT, and it's only partially true. Yes, you two probably had issues that led to her to lower her boundaries and look elsewhere, but as noted above:
a) it doesn't excuse it -- she should have tried to work with you, or had the integrity to end the marriage before cheating; and
b) affairs are HIGHLY ADDICTIVE. So while the OM may not have INITIALLY been the "reason" why she didn't want to work on the marriage with you, I can assure you that -- at least chemically/physiologically -- he became the main OBSTACLE to it.
