Being that by the time I've read this you are already at or been to the meeting with your W, I'll just say I'm keeping my fingers crossed that it goes a smoothly as possible.
I like the idea with starting seperating the finances, seperate accounts, credit cards, etc... It should the most straight forward to accomplish amicably and hopefully that will help set a tone that is less adversarial in the following steps.
The benefit would be your W getting the sense of progress in an area without having to fight you tooth and nail every step of the way ... a more positive outcome, thereby increasing the chances she might be more willing to be cooperative with future steps.
