You seem to be sounding good. One suggestion -- Why not take it one step at a time?
Step 1: change the dance -- get unenmeshed, set boundaries, enforce them, and so on, let go of the old M (FOR YOU)
Step 2: see what happens with W, she will HAVE to change in someway, make new movement of some sort if you change the dance. (ALSO DO THIS FOR YOU BECAUSE YOUR LIFE WILL GO BETTER KNOWING YOU GAVE YOUR M THIS CHANCE TO SUCCEED.)
Step 3: set a deadline -- 6 months from now, a year, two weeks, whatever. When you reach the deadline, then evaluate whether or not you want to move on. (THIS DEADLINE IS VERY IMPORTANT, it is what you remember when you feel like a victim. YOU ARE NOT A VICTIM, YOU CHOSE TO BE IN THE SITCH FOR A PERIOD OF TIME FOR YOUR OWN REASONS.
Step 4: "Move on" or return to Step 1, whichever you choose as the right step for YOU.
So, to sum up, my suggestion is that you do this important work on yourself and see what that does to shake up the R between you and W before throwing in the towel and moving on.
If you have to "move on" to get unenmeshed, then you probably aren't really getting unenmeshed. Whether it is another R, a D, or both that you use to "move on" is still really all about W and getting distance from her, but the ties will remain thick and messy. Get unenmeshed first, then you can move on cleanly if it turns out to make sense for you.
