I thank everyone who has posted so far, it has been very insightful.
I hope to be able to forgive and get back to a place were we can be friends. I'm still rather hurt right now, the way it was done though unintentional was extremely painful and I'm dealing with feeling very hurt.
To her it was not okay for things to be unbalanced. I know her anxiety and I know that is what took hold, I had helped her work through some of her other anxiety. That is one thing that hurt, she worked through anxiety with other people, it hit our relationship and I was a casualty. I don't know if that is a fair feeling, but that I what I currently have.
I think she was getting too confined, too stressed, too pulled. When she emailed her issues everything she said really just said "too much"
She was very much focused on being unlabeled, let it be what it is. She later said she had not planned for anything more than a secondary only to say a few times later she wanted me to be as equal as possible to her husband. I don't know if the NRE wore off or if her issues and anxiety just exploded us, but instead of being able to work, maybe back off, take a little time she just ends it.
There are things I have left out her around her marriage that I just don't want to air. I will only say they are still working through things. I don't believe jealousy was an issue though, if it was it never occurred in front of me.
As for never ending it, she spoke of that fear that I wouldn't. I though always had a feeling we would part ways eventually, maybe I would have drug it on too long, I can't say now. I however did not expect it yet, but maybe I missed how much of a strain it put her under. She had seemed happy, very much present and committed shortly before. She did say though, when she dropped the issues on me all at once (by email) that she had not intended it to be a breakup. I think the guilt of our imbalance is the final piece that pushed her to that.
I'm tired this morning but not as anxious, I hope this came through as coherent though.