I really wish I had more advice to offer you here other than what's been stated by others before me, but I would emphasize that it is YOU that needs to throw yourself back into your M. I guess my real concern, which was also expressed by GH, is that it seems everytime things get rough, your W has thrown around the idea of a D. This is definitely an issue that must be addressed in the context of a continuing relationship, but let's not put the cart before the horse. You must do whatever it is that you can do to win back trust and the heart of your W. This doesn't mean that you have to be a martyr...it seems that you have owned up to your decision and have been making amends, but it does mean that you have to be open and honest with her.
"Achieve success, but without vanity; Achieve success, but without aggression; Achieve success, but without gain; Achieve success, but without force." Lao Tzu