GWN, I'm glad you posted. You sound more grounded these days. You will have good days and bad days for a while.
As for his mother, she sounds like a piece of work. Who is she to tell you that your marriage was not to be? I don't think I would respond to her email for a very long time, if ever.
Your xh is fragile and yes, kindness and compassion are what is needed when dealing w/someone who is going through mlc or life changes. The journey isn't about us at all, but about them.
From what you've posted, he's starting to work on some of his issues and I'm glad he's on medication to help him sleep. He's still got a ways to go, but you already are aware of that.
When I read the end of your posting, I thought to myself "GWN, you and your xh are now beginning a genuine friendship and it's nice to see that he appreciates you checking in."
GWN, you've grown by leaps and bounds and have been an excellent example of patience and compassion. Your xh doesn't realize just how lucky he is to still have you in his life. I do hope that he will finish up his crisis and come to realize that he was not the reason his authority figures treated him the way that they did as a child. I hope that he will mature and become the man he was destined to be.
Take care.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.