It sounds like the two of you are out of sync. She was winding down and settling in as you were gearing up and branching out. It seems like you met on an overlap. Like two trains going in opposite directions stopping at the same train station on their way.
If you can’t find a way to accept her past and curtail your desires to get in sync with her, this may not be the relationship for you.
As far as her past goes the best lens to view it through is that her past led her to you now. She got that out of her system and is looking to focus her attention on you and evolving the relationship. If this isn’t right for you, you have invested that much time, you’ve learned a lot, and going your separate ways in search of more suitable partners might be warranted. Sometimes the timing between couples aren’t right.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral