I hate getting the blame too, but it's just their way of trying to slime their way out of the guilt they feel for banging someone other than their spouse.
You would think that they would just call it a wash and forgive each other, but no-o-o-o-oooo. For some reason, YOUR sin is SO much GREATER than Ms. Perfect's indiscretions.
I'm glad you are moving forward because she will never stop beating you over the head with this.
Whenever she starts in on you again, just let her keep hitting a brick wall. There are good women out there who will treat you right.