It sounds to me like you are in a perfect position to interact with her in some way that is *different* from your usual ways. You were married for 19 years. What were you like in the beginning? Did you take her on dates? Did you ever *do* or *say* anything romantic?
Clearly, if you've been doing some Strong DBing for 10 months, and nothing seems to work -- DO SOMETHING Different! Have you looked into her eyes and spoken to her with kind gestures, such as "I realize you want this divorce, but it is not what I want. Can you think of one thing I can change to make you happier than you are right now?"
Anything is better than just sitting back and watching her escape into darkness. Just my two cents.
(((((((((hugs))))))))) poet
P.S. Keep talking to me. Tell me specifically what you were like 19 years ago whenever you two met. What drew her to you. THINK!