This is an interesting discussion.
I'm going to go off on a bit of a side track -- taking on board everything Mermaid and HB have been saying.
This isn't about our MLC spouses... but about MLC in general.
One of my very best friends, who's never been married, went through an MLC around the time she was turning 40. She wasn't in a relationship, so didn't have anyone to hurt in this way, but the crisis was still very real. Perhaps some would call it a transition rather than a crisis, but in any event she found herself unable to continue with life as it was, took a lot of time off work, went all over the place looking for what was missing.
Perhaps for her it helped that she eventually realised that she was depressed and sought treatment, and did spend the time figuring out what she wanted from life.
But during that time she pretty much dropped off the face of the earth. If there is one difference, it is that she didn't blame her friends.... but had she been in a relationship she may well have abandoned it, as she reallly was re-thinking every single thing in her life.
She is highly intelligent and educated, has always held responsible and intellectually challenging positions, that kind of thing. So she was a shocked as anyone to find herself in this situation.
She came through, reconnected with everyone and made some pretty big adjustments to her life, but in the end is still living 'her' life, rather than having gone off to a completely different one.
And this was before menopause...
Just another story...