Hi Lee - first off, I will never get an apology from my H. Not a verbal one anyway.
Definitely read and re-read DR. It has helped me to crawl away from insanity back to the person I truly am, and for now my H is responding. Even if he hadn't or if things still end up with a divorce, I am in a better place.
As for the kids, I think you can empathize with them but obviously don't blame your W. Let them talk to her about how they feel - don't put yourself in the middle. To help them along, distraction works great at that age. Make them laugh - play chase - tickle - whatever gets them going. Reassure them you both love them if they still get worried.
He: WAH Me: LBW Precious: DD
~ I'm grateful for every day I have to improve the way I relate.