Peter, I would not move out if I was in your position, and certainly not before I spoke to a lawyer. Besides, if your W really wants to file, she will file whether you move back or not. I'm of the mind-set that whomever wants the separation should be the one to move out. She should not be making threats like that either.
Anyway, I'm sorry about the Anniversary bomb. I got one of those too. Tacky. Even if I wanted a D (and quite frankly I'm feeling like the WAS these days), I wouldn't be so insensitive.
Hang in there, Peter. See a lawyer and do what's best for your kids. (Personally, I think that's staying in the house).