I have seen this happen to the nicest people, so don't think it's you. Sometimes a person we think is safe to love suddenly does things that we had no idea they could do. I think that you are getting a picture of who she is so there is no point in continuing to investigate. It's hard to grieve something like this, it takes time and patience and building up the will to work on self and get strong and even find someone else that can appreciate you.

I am very sorry, wish I could have a magic wand to wave to take this challenge away for you.