Ok, so I may have had a few salient facts mixed up...couldn't find all your early threads, The Great Sandi Experiment and the one preceding that...but you did a good job at DB'ing once she was hinting at separation (and in your further defence, all of ours really, nobody thinks she's reeeallly serious during the first month or two anyway, so the pressure being brought to bear is due to that, i.e. how can it drive her away if she's not really serious...even she isn't sure in the early stages). But when it becomes clear she is serious, then that is when DB'ing becomes important...which is why I'm thinking the fog will clear in your favour. "Fog" is really stubbornness for exes like ours I think, they would rather live with regret than appear to others to have acted in haste (without fully thinking it through), by making a decision to give it another shot for the sake of the family.

And while the cost of health insurance may appear to be a good reason to avoid formal divorce proceedings, you can bet she would figure out a way to get it done (like she has with respect to selling the house, moving out, splitting custody, etc.), IF it was important enough to her. For example, if her new relationship was important enough, and the new dude is getting annoyed and asking why she's not yet divorced, her still being married is standing in the way of a getting re-married...yet she's done nothing about that, but would have you believe she's "happy" (or happier) with the new dude. Don't forget, the biggest threat to his relationship with your ex is you so he wants her divorced. I say until she's re-married, you will never be off her radar...and any new guy, a guy that's NOT the father of her children, has little room for error.

I have taken a different approach as of late, not being nice (not mean, just very dim, very distant), allowing no cake eating, no updates on the kids, and calling her out on her $hit, see what that brings. Probably nothing, but DB'ing hasn't to this point brought good results either, so why not? Can always go back to DB'ing, it's a long, long road and really not over over till someone re-marries or both are completely indifferent to the other (and that can't be the case if there is still anger and emotion emanating from both sides).

Apologies to all readers, I'm the king of run-on sentences.