Woody Allen once said, quoting Groucho Marx, that "I wouldn't want to belong to any club that would have someone like me for a member."
The response to your wife -- that you will SOMEDAY reiterate to her again -- is this:
"So let me get this straight: you responded to your unhappiness in our marriage by deciding to have an affair, and when I found out about it, I was supposed to . . . woo you? Fight for you? Be okay in an open marriage? What? I'm sorry, but not only would that violate my OWN boundaries of personal integrity, but I don't even understand how you would WANT to be married to someone who WOULD do that. Maybe your OM will be that for you, but that's not me, and frankly I LIKE me right now."