One of the "myths" that rarely gets addressed around here is that "The LBS must have done something to harm the relationship, and make the cheating spouse ripe for an affair, and they have to 'fix' those things to get their walkaway spouse back."
Well, yes -- often. Maybe even usually.
But Dr. Harley's research (as well as others), have uncovered a good % -- I think it was 20-25% -- of affairs happen in GOOD marriages. And by "good" I don't mean some DAM, or clueless wife, THINKING it was good. I mean they WERE good, healthy (maybe not perfect), marriages.
I think the key is to immediately separate the one group from another, and then give our advice accordingly.
Personally, I try to first determine, "Is there an active affair going on, or not?" About 75-90% of the time, there is, at least an EA.
Then, if there is, is this one of the 75% of marriages where the betrayed spouse played a significant contribution in the dysfunction of the marriage, or is it one of the 25% where the cheating spouse is cheating merely out of some combination of boredom, entitlement or "if it feels good do it" mentality?
Because, in my opinion, if you treat one of the 25%'ers with a bunch of "Honey, I knew I was wrong, and please let me try to win you back," you will only make the situation worse.