My wife had an emotional affair, now were trying to work it out, why does she dig for dirt on me now?

My wife had an emotional affair with her X busband last summer. He had gotten remarried and could not let her go. He would talk for hours and hours, and when I discovered this, lies and secrecy were instilled to hide it. Im talking phone cards and there was even a fight about a trac phone bought. Then after this was over, came another emotional affair on Myspace with an x boyfriend. It was vicariously relayed through text, messaging, and phone calls with her nest friend at the time. After seeing this we seperated for a couple months. During that time I had called an X girlfriend whom I did NOTHING with, nor even led on that I wanted to with her. I realize it wasnt right that I called her, because two wrong dont make a right. I have also forgiven her for these past emotional involvements. We have moved on and are having resentment, but WHY does she constantly dig for dirt on me like she has to watch her back. She discovered I talked with X and declared SHES DONE. I barely talked with X!