I mean, what's the basic mantra in the DB community -- figure out what you did 'wrong' to contribute to this outcome: "I think I wasn't supportive, but of course that's just my perspective, so it doesn't really matter."
This is a fascinating observation, and many (Gucci, for one) have posted about it: the natural tendency in DBing to start with the assumption that the betrayed/left-behind spouse is somehow deficient, has done something "wrong," and therefore needs to be "fixed" in order to attract back the wayward/walkaway spouse.
And this is certainly true in many, many instances.
But not all. I believe it was Dr. Harley who found in his research (and practice) on infidelity, that about 20-25% of the affairs happened in perfectly healthy marriages. And Gucci (and others) has posted about "Sometimes, you really DIDN'T do anything wrong -- sometimes it really IS just THEM." (I'm paraphrasing).
Really, if you follow the MLC forum at all, which I do at times, they work from the perspective of it's ALL about them -- it's their "journey."
Too many DBers, in my opinion, try to work with this "fix-it list," articulated to them from a fogged-out wayward/walkaway spouse, many times chemically-fueled, and find themselves in a hopeless, cheeseless tunnel of "self-improvement."