I'm sure your head is spinning. MLC is not a nice adventure in the game of life. You've shown such compassion and kindness towards your h throughout this difficult time and yet, he still doesn't get it and probably won't for many months, even years down the road.
I'm not at all surprised that he would write you a note that he didn't believe you didn't tell him. Unfortunately, they either don't "hear" what we are saying or they think we are threatening action unless they shape up. Your h is going to have to learn to be responsible for his actions. It will be interesting to see if he turns into an angry man because the divorce is going through. Some are really nice until the action begins and then turn into monsters. I do hope for your sake and the children's, he won't be one of those monsters.
You've done all you can and have made many attempts to save your marriage. Now, it's time to take care of you and your children, protect yourself no matter what.
Take care of yourself, be kind to yourself. Okay?
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.