I am from the MLC board. It does sound like your H may be having a MLC. He actions sound very similar to how my H started out.
The shutting himself from everyone is classic. Mine did that for two years before he left. That is not to scare you, not all MLCers leave.
There are resources at the top of the MLC board that might give you more insight to understand if MLC is what your H is going through.
It is a long haul and will require more patience than you ever thought you possessed. You can't fix this for him. He has to work it out for himself.
As far as the kids are concerned you will probably have to step up and fill in for your H with them. If he is going through MLC he is all about himself right now.
As far as intimacy, it is a way to stay connected to him and a personal choice. Again, not all MLCers have affairs, but it seems the majority do. Please make sure that if you remain intimate that he is not having an affair so that your health is not at risk.
While your H is on his journey, MLC or not, take a hard look at your M and own your part in its breakdown. This is an opportunity for you to work on yourself, and it sounds as if you have started.
Remember, you can only control you. Lay your H at the Lord's feet and let Him work on him in His time.
