One of the things that used to stand in the way of my leaving was the idea--that XAH reinforced--that if I left, it was the END of the world. It really wasn't, for me at least. For me, it was a new beginning. It began a period of rediscovering myself, gleefully I might add, and of finally feeling a huge burden lifted off my shoulders.
Evenkeel, from where I sit, you're doing immensely well in identifying elements in your wife's behaviour that are damaging to you. I've seen a lot of people here at SR who waver for a much longer time than you have, and who are still unable to see through the b.s. and false promises. So, kudos to you for this!
I understand the need to be "fair"...for me, it came down to the need to be the "Good girl" in my XAH's eyes (and perhaps in the eyes of others). But in this case, she has been UNFAIR to you and your kids for the past few years. Also, who the heck cares what other people think of you and your marriage? They are not the ones who have to live with a spouse who is DEEP in her addiction and DEEPER in denial. It's a horrible rollercoaster ride and you deserve to get off! So, let the rest of the world suck on their opinion of you...you are doing what you feel is best to look out for yourself and your children.
IMO, you should keep looking at alternate living arrangements. You can always back out later if things change. But realistically, they won't for a while, so you need a SANE place to home come to.