This is an awesome thread and very similar to my situation. I don't want to hi-jack his awesome thread so I'll be brief. My current wife (my second), before I met her, had an eight year relationship with a guy who she cheated on regularly. Like once a week. After it ended she got with me a few years later and we talked and I told her how my first wife cheated on me a lot and yet I didn't divorce her, she divorced me, oh and later regretted it and tried to get me back. Too bad, I was already crazy in love with my new woman. Anyway, my second wife later told me how because I never expressed anger about my first wife cheating on me she felt safe in telling me she cheated on her bf for years. She openly admitted it to me just like the OP's wife here has told him.
She obviously knew I was "cuck material" and she wanted to experience the fun of cheating again and with me she knew she could, which is why she pursued me so strongly, even being the first to suggest we get married. Some women can love a guy and still have crave the excitement of cheating. The OP and me have married the same type of woman! Life is never dull!