Hi MLC forum!

I am coming over here from the newcomer's forum as I could use some advice and help on how to conduct myself and react to H's perplexing behavior. I know that many people assume MLC when nothing else 'explains' a spouse's behavior, so I am open to the fact that it may or may not be a MLC. But, here is a little recap of my situation:

H and I are approaching 40 we have 4 kids and a business together that requires a lot of travel for H. He has always been slightly insecure and needs people's attention and affection to fill his self-worth (for those of you who follow attachment theory, he is anxiously attached and I am securely attached). H had a rough childhood with a father who told him he was never good enough and a mother who smothered him. They D'd when he was young and he was abandoned (sent to boarding school) at a very young age. We met and married in our mid-20's and had what the whole world thought was a fairytale relationship (me too). We were desperately in love, all of our children were planned and excitedly welcomed into our world, we were a great team.

In the past couple of years, our business has taken off and he has spent most of the past few years traveling while I held down the fort at home. His job is very stressful and about 18 months ago he had a near breakdown (if not a full-fledged one). Since then, things haven't been the same, but I chalked it all up to stress and tried to support him as best I could.

10 months ago I discovered he was having an EA (although highly likely it's a PA) with a married client whom he sees several times a year for work. I lost my mind and did everything wrong. At first he was desperate to please me and maintain what we had ('I love you, my goddess, you are my everything'), then he started vacillating ('I don't know what I want') and now it brings us to today ('I have never ever been happy and I want a D'). He moved out and we are navigating co-parenting our children while he has no work/travel due to Covid.

What I am struggling with most is that he has so much self-pity/pain/guilt/shame that he can't eclipse his own feelings. Although I am recognizing that I can't expect an apology or recognition for how his actions have hurt ME, I have been hoping that he attempts to put aside his own pain for the sake of the children. He takes everything they say and do personally, even construing things they say that have nothing to do with him to being all about him.

Is this part of the MLC process? I see so much of his childhood rearing out in this process (his dad was the same age as H when his dad did the same thing to my MIL). What is my role here? Let him go completely and give the kids a stable, emotionally normal base in my home? Any advice on how to deal with the spewing/blaming one minute and 'why can't we be friends??' the next?

Thank you for reading my story!

Sage