Tiredlove, I believe I know what you're going through. I'm going through very much a similar situation where I will likely see my ex and her live-in boyfriend at her brother's wedding. I happen to be that guy that was her first love and known her since grade school (we're 30s now). She also has kept every letter and note since grade school to this day, there's a lot of similarities between your girl and my ex.
In a relationship you should dump your baggage on each other in the beginning and begin to work it out. That's the way to build a bond. All I can say is that I sort of know that her boyfriend that she has moved in with is probably going through a similar situation, feelings and thoughts you might be... especially if she is being honest and transparent with him about herself. I would hope he's handling it well and accepting her for her imperfect, messed up self, because in the end, that's what it's all about. Unconditional love. I think you're on your way to finding it as well. I wish you the best and to persevere, what have you got to lose except a few years of your life if it doesn't go well? And if it does... you've made it through one of the best challenges a man can face in his lifetime.