yes, it seems the one think we can count on is the behavior of our alcoholic spouse. They are so predictable. And now fully armed with the collective wisdom here, I find I am no longer alone. That all her "gaslighting" or crazy making, or what ever she does is stereotypical of most.
You are wise to recognize true change is an elusive behavior.
Stay strong. stick to your guns. And remember, he will say and do what ever he he needs to in order to get what he wants. I predict as you approach actually leaving and he sees you are serious, he will start quacking and say all the things you need to hear. I find it helps to visualize them as a duck, and pay no attention to the words. I try to make them just as meaningless to me as they are to my alcoholic wife.