Hang in there, I know it's tough but nothing you've posted is new here. Your WAH is thinking he has found happiness, the D is the door to that happiness... It is not till he walks through it and things become real for him that he will have to start dealing with reality. During this time, D or not you have an oppurtunity to work on yourself and be better and stronger because of this, you did not ask for it... But this will not destroy nor define you. It's time to let him go for a bit and you owe it to yourself and your kids to find that strength deep inside you to do this.
The first thing I did... I got out of bed. Then... I made it. Every damn morning... Make the bed... Take the time to make it perfectly, this strata your day off with a sense of accomplishment.