So I've been reading and sitting on my hands in order to keep my response to myself. Well I absolutely can't stand it anymore.
Pretty, your husband's personality traits seem to be pretty consistant with someone who finds themselves in this MLC confusion. Of course your ex was always this way, but until now he always had a distraction. We first get married, then we buy a house, have our babies, focus on career. All of these things tend to keep our spouses focused on other things besides their buried discontent with the people THEY are. Inspite of the mistakes that you may have made in your marriage this isn't about you, and it never has been about you. I'm telling you this because if he really wants out it doesn't matter what you change because it will never be enough.
I am not a new poster as my sign up date indicates. I had to rejoin since I couldn't remember any of my old info and I'm writing to you because Braveheart's comments were spot on. No one knows how this feels until they have walked the walk. There are no guarantees with MLC. I don't really understand what your husband is getting out of MC unless he's trying to figure things out. Usually most MLC'rs agree to go to MC to appease us and to make it look as if they tried. However, those appointments don't usually amount to more than a couple under their belts, when They decide that they really aren't working for them. Maybe your ex is the exception here but it shouldn't take too long to figure this out.
Yes, this is a Divorce Busting sight but sadly enough most will not be busted, which is why the best advice we can give is to protect yourself and your children. If this is a true MLC you most likely have a long road ahead. My ex started on his mlc 7 years ago and it is only now that we are starting anykind of remorse at all. The little they give us, to them is HUGE, to us it barely matters once we have healed. These MLC'rs are a different breed. They can walkaway from a spouse, children, family, friends, pets and a life in order to find a piece of themselves that they feel they missed so long ago. Believe me, you could have never been prepared for what you are faced with!