mach1, that was dead on. Scorp, my W left too. Even though I had considered it because repeated attempts had failed over the years to change or fix the M, I stayed. she finally bailed.
I heard later that she'd been trashing me for years to our kids, friends and family, and planning to leave as soon as so could figure out how to do what she wanted in life without me (our earnings are very different...she has expensive hobbies).
keep your head up. protect yourself and your kids. She may get angry, but she'll respect you for standing up and saying/doing what is right and what you believe in.
I ended up filing for D. my W showed no sign of coming back and was trashing me and lying to me about stuff. We have no separation here in my state. Either you file or you don't. The only way to make sure she couldn't hurt the family financially was to make her accountable (legally) for her own expenses. I told her I don't want this...but, there doesn't appear to be another way at the moment....
good luck.
me: 47, W:49 M 16.5 years T 17 years Three kids - D17,D14, S13 Heart 2 heart about M 11/8/13 Bomb drop 11/29/13 W moved out 12/5/13 I Retained L 2/20/14 D filed 3/17/14