Something has got to give and I don't think it has to continue to be you.
You've been more than patient and understanding with CAW. You've been a support to her when she's gotten into her (I believe self induced) depressions. You've allowed yourself to be used and abused and walked all over for the past 2+ years in hopes of what? In hopes that this turn around will last or that om and the distancing wont rear their ugly heads again.
KAW, I know you've tried distancing in the past and that seemed to work a bit to draw CAW back in your direction but no for keeps (a the age old was that has to know the changes are for real) What would happen if you decided to put your foot down and tell CAW enough of the bs fun and games either get real about this marriage or get out NOW! I know it is not what you want and certainly not what dd10 wants but this pain has to end...you need to stand your ground and stop waiting for it to fall out from under you.
I know others may find my post to be harsh but KAW I've been posting to you for how long now? enough is enough man!
of course your other option is to continue the act as if and gamble that EVENTUALLY caw will wake up from her dilussions, but how long might that take? Now it also sounds like you not only face her leaving for creapy looser om you also face the possibility of her running of with dd24