Sounds like your things are thawing out between you and W. Keeping the communication lines open, even if it is just about the children is a good start.
You seem to have really taken the big step to moving on and complete detachment. Necessary at this point. But at least it sounds like you two are becoming friends again. Friendship keeps the doors open. Keep fostering the friendship. You will have to deal with this woman for the rest of your life...proms, weddings, graduations. All with this person. The least you two can do is become friends for the childrens sake...and you never do know what can happend down the road.
Me: 30 EX-H: 37 DD: 5 Separated 6/07. MC for months, EX-H quit MC. Divorce Final 8/14/08. Trying to move on with new life.