Not sure what to tell you gutwrenching, as I am only about a month into this myself, but I really feel for you. For all of this to come out like this and at this point has to be devastating.
I hope you and W can each find your way to what it is you want out of life and this R and work towards it eithr together, or individually, whatever you decide.
Hang in there and wait for some of the pros to ive you better advice. I actually see her breaking down and telling you all of this as a positive step in that she is coming clean. Maybe she really does want this to work with you, but will have a very hard time overcoming the guilt. You will have to help her tremendously if this is what you really want.