For most couples who come to me - especially in the aftermath of the revelation of an affair, when they are in a state of crisis and fear the loss of a predictable future - they start to have conversations for the first time about love, sex, monogamy, and marriage. Most couples don't negotiate or don't even converse about any of these things until the crisis of the affair has actually forced them to. Why does it take infidelity to get us talking about the stuff that should be there from the start?