They become aliens to us because the behavior is not what we have been use to....so, I refer to them being taken as passengers on the Mother Ship. What would you call it? Rolling in the deep? One flew over the cuckoo's nest? Honestly, they become so emotional and irrational at times, they do tend make us wonder about their sanity. It's difficult to rationalize w/someone who is very emotional and angry at the world.
Why would you say that they are fed up? MLC is about their pasts and what transpired long ago. They go back in time to revisit their childhood. It's about childhood issues or something that stunted their emotional growth. It's about not being validated and recognized at that time in their lives, it could be that a sibling was the golden child and got all of the recognition, it could have been abuse, etc. How they are dealing w/their crisis is all about emotions. But, I can assure you, this journey is all about them and what they need to do to heal themselves.
You can only own 50% of the relationship breakdown and whatever you do, do not take on his part of the breakdown because he will most certainly think it was all about what you've done or didn't do to make him happy. Don't drink the Kool-Aid he serves up and yes, they do rewrite history very well.
Now I can understand a WAS being "fed up" in not being heard or recognized in the marriage, but that is a different scenario than MLC. However, you would do the same things, i.e., give them space and time and no contact unless an emergency arises.
Whether you want to call their alien behavior that of an alien on the Mother Ship, pod people or rolling in the deep or crazy/irrational...they become the exact opposite of the people we knew and loved pre-crisis.
I urge you to read the homework and visit around the forum and most importantly, educate yourself on MLC and depression. This crisis will not end any time soon, so buckle up and be ready for the roughest ride of your life. The more you learn, the better you will understand what he's going through.
P.S. I do want to just say this, they do tend to toss us aside during the crisis because the inner child comes out to play and w/that child comes all of the emotional baggage that they have stuffed down deep into their souls for a very long time comes to the surface. The love that they felt for us is then stuffed down into their souls until they are able to face their issues/fears, accept that they had not control over what happened and can then begin to grow up from that time on. For some, they may remain stuck in crisis forever. For now, pray for him and continue to work on you.