Most Helpful Girl
if she does not want to talk to you at all it is because she is feeling pretty bad about the break up.
Give her the space she is asking for, because pestering her will only make things worst.
Thing is, you fucked up. And even if I don't know what it is you where emailing about, I can make a wild guess and tell you that it was still cheating. Even if you never acted on it phisically.
I don't think you would have liked it if she was chatting up some other dude right? How would that make you feel about her?
Once the trust is gone, it is almost impossible to go back to how it was before.