It sounds like there are more than a few problems going on with your H. MLC or not, what is going on is plain bad behavior. I've always sort of disagreed with the "experts" on MLC anyhoo. Just because you're questioning your life doesn't give you the impetus to cheat on your spouse...a lot of folks go through some crisis in their lives or emotional problems and don't end up cheating on their spouses.
If your H is passive-aggressive, then there is a boatload of problems there. It is not easy to deal with a PA, and it can drive you batty. My ex was very PA, particularly the last few years of our M just before we D'd. They won't make a decision actively but will wait for YOU to get p@ssed off enough to force one. They won't make a choice or informed decision about anything but will wait for holy heck to break loose before they move on anything.
Also, my thinking is you can't really compare or contrast the development of an R with "stages" of an MLC. Relationships DO have their distinct phases, and particularly after a honeymoon phase there is always a power struggle because the hormonal high isn't there like it was at the start of an R--it's the same when you marry too. But that doesn't necessarily mean the end of an R. Your H sounds like he's still out of it, and isn't thinking clearly. So putting all of that together, it may not be possible to "chart" out what stage/phase he's in and then put it to a calendar to say "ah-ha, this is when he'll 'wake up.'" Some of them never do "wake up" the way we want them to and some do come back, but it's a brand new relationship for each spouse and each spouse has a lot of work to do--one has a lot of healing to do in order to recover from the trauma of an A and the other has to do a lot of work to support and understand the trauma they've put their spouse through AS WELL as learn new coping and relationship skills.
You're doing great. I hope you can continue to encourage your H to bond with the kids...and I hope you can continue your R with the MIL no matter what. From my perspective, she's a great resource to you. Yes, MILs may want their child's happiness but she may also be grounded in reality as well as understanding what's going on beyond what you can see right now. I wouldn't necessarily consider it negativity.
Also, I have another twist on exposure. If your H is particularly PA, it may not be a good thing. When I "outed" my ex, it became nasty. He resented it highly because PAs like the world to think they are "good." Mine looked like a frigging altar boy to his folks...and on the surface, I could see that. Catholic, 4 kids, 23-year M, nice home in the burbs, white collar job, kids in college, yada yada yada. Blech. What that man did shocked them and they took him to task for that and truthfully gave him bloody hell. He took it out on me and so did he OW. Just be careful as you think that through. I laugh at it now because his reaction was pretty childish, but it can hurt and it can sting--you!! You may not want to go through that emotional rollercoaster.
