A stupid betrayal to my wife and family?

Ever since my affair with my old flame was exposed, I tried to change myself but deep in my heart, I do missed her. She frequently contact me via email and I am trying not to be too emotional with her again as I do not want my spouse to be hurt like before. My g/f is someone mistress for almost 20 years( divorced with 2 kids) but claimed to be unhappy with him, while I am married for the past 22 years to a very supportive wife. Should I tell my lover to stop contacting me or do I just avoid her calls? I am rather confused and indecisive due to my feelings for her. We had an emotional and physical 4 months till her man found out. Everything blew into pieces and she is at the moment trying to patch up with her man. Should I trust this sort of woman who confide to me, had with me, then went back to have his man again. Or vice versa. I am hurt and not sure what to do. I know I am a real s to betray my wife but I lost my control when with my g/f. She told me she will never want his man but now she goes back to him and continue to sleep with him. What am I?