I sort of see the whole "MLC" thing the way I see the "ADHD" thing. For every kid put on Ritalin, there's probably 5 more who shouldn't have been, that are merely active, healthy kids (usually boys).
Whether or not a "life crisis" exists (and I don't think they conveniently come at "mid-life," whatever that even is), I don't personally believe that the way you deal with the walkaway/wayward spouse's behavior -- or your overall sitch -- should be any different. You should still seek competent legal counsel if your spouse is talking D, you should still put healthy boundaries in place, and you should still not enable any affairs in any way shape or form.
I don't buy the whole distinction between "MLC affairs" and "normal" affairs. There's NOTHING "normal" about infidelity, and I advise people to attack it the same way.
I do think there are different types of IC that are probably called for, based on what factors the wayward spouse feels drove them to their destructive behavior.
That's just me. That view may not be in the majority, and it's damned sure not going to be in the majority on the MLC forum. I just see way too many sad, sad people stuck in limbo for YEARS while their adolescent spouses cheat on them over and over, and largely get a pass because they're on they're "journey."
(((spew)))