I know that I played a role in our situation and am working very hard at making myself the best person possible.
STOP ALREADY!!!!!! Sure, we all have improvements we can make in ourselves, no one is perfect, but in this situation, it is HER that has the problems, okay???? You're a good guy and a good catch - except for your co-dependency white-knight-syndrome stuff. Work on THAT, okay?
Perhaps you should read Dr. Laura's book on the Ten Stupid Things Men do to Mess up Their lives - I haven't read it but I'm pretty sure your sitch would be in there somewhere.
Sorry to be so harsh - believe it or not, I am in a reconciled marriage and I totally believe in DBing. BUT - I think it's a mistake to continue when serious problems like these appear BEFORE marriage. AFTER marriage you have a commitment to work through things; BEFORE marriage is time to shop around and make sure you're a good fit. She's not a good fit, man, okay?