It sounds like your W needs to GAL herself. I know you say she suffers from depression, but if she gets busy with something, that would surely take her mind off being depressed. Does she have any hobbies or activities that she ever had an interest in trying? I guess the trick would be for you finding a way to get her started into doing something that would make her happy.
Right now it seems she sees you as doing so much better and happier in life than her and that only adds to her depression.
Seems like you mention that she laments a lot about her loss of the OM. Have you considered that she might be so depressed as to be suicidal? I know that I am taking no chances with my W even though she does not seem depressed - just angry and irrational. That is the main reason why I got the guns out of our house and over to a 3rd party this afternoon.