How to Do It She doesn’t know me as well as she thinks she does. Photo illustration by Slate. Photo by mediaphotos/Getty Images Plus.  How to Do It is Slate’s sex advice column.  Have a question?  Send it to Stoya and Rich here.  It’s anonymous! Dear How to Do It, I’m a man in my mid-forties, married to my wife for 10 years, together for 20. We’ve built a life, a family, and have been, for the most part, happily married. But there’s something I’ve been carrying on my own for a long time—something that could end our relationship—and I don’t know how to deal with it. During our relationship, for my sins, I have had several sexual encounters with other men—not full intercourse, but certainly still a betrayal. There have been half a dozen occasions, all behind my wife’s back. I haven’t done anything like that in the last couple of years, particularly after a close call where I nearly got found out. That was realization enough to stop, but it hasn’t stopped the thoughts or my curiosity.…