I feel for you having been through the same in November 12.
Have not read your whole sitch but wanted to wish you the best. I am probably one of the ones where my sitch seemed to have improved after W moved out so don't give up hope.
Keep strong and make the most of your interactions with W unless your sitch warrants going dark. My guess is the space might do her good and IMO sometimes they have to leave to realise what they have left behind....but the desire to get away is just too great for them.
Keep working on you and GAL and quality time with kids...otherwise time will feel like it stands still when you are home alone. It still feels weird for me coming home to an empty house but I keep busy each evening and I am starting to get used to my own space (and starting to enjoy it).
