"I want to be able to ask her if she is willing to work on things, why no do it while separated and not divorced?"
Why are you fighting it so hard? If getting a D will help her to work on the R, then wouldn't you be willing to do it? I know, it sounds crazy to me, too, but that's what she keeps saying. You are the one fighting the D so hard. Why? Isn't having a R with her what you really want?
You are scared to death of a D! Why? You don't have a M, now. Remember, it died. You don't have her as your W, now. What will be the difference after you sign some papers? You said it yourself, what do you have to lose? If getting a D will get the two of you together, then why are you dying a thousand deaths a day over the fear of it? What does that M license give you right now? You've already lost it, but according to her, there just might be a chance once she is legally free.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!