It boils down to two simple questions: "Do you love her and does she love you unconditionally?"
If the answer to those questions are yes, then you should really focus on working on your relationship and not think about the past....
Avoid thinking about what you could have.. what you should have.. and what you would have...... (AKA wuda-cuda-shuda)

I know its harder said than done, but if you truelly want to be happy in life, take my suggestion.

Good luck.