I think there is a lot of overlap in the ‘symptoms’ of infidelity and MLC - Emotional distancing from the spouse, kids, friends and FOO; angry and being critical toward the spouse; overt attention to physical appearance; spending money like water, etc. In my opinion, one of the major differences between a garden variety walk-away spouse and MLC is the presence of childhood/teenage issues. Of course, this, too, can be ‘found’ if LBS tries hard enough (you will see what you want to see), considering that not many people can claim a perfect childhood with perfect parents.
I agree that not all situations on HS are MLC related and it could be a person having an affair and moving on, or taking stock at midlife and deciding that they want something different. It is understandable that LBS prefers MLC explanation, because, then, there is some chance that their spouses will come back, so we read. It may also partly explain what I see as some LBSs projecting their spouses on to ShockSis and taking it personally if she is challenged. She said she always loved her H deep down and that she wanted to get back with him. Probing questions, observations and opinions presented to ShockSis which are not ‘thank you’s and praises, perhaps challenge LBS’s own dream that his/her spouses really loves them deep down and will want to come back to them eventually? One needs to believe her spouse is in MLC in order to validate this ‘dream’ and not think of oneself as gone cuckoo.
I think that it’s not only LBSs who want to believe their spouses are in MLC. It’s possible that the errant spouse may latch onto the idea of MLC as a fog to obscure one's infidelity. You know, a tailor-made ‘reason’ why they behaved dishonourably to escape one’s full accountability.