I first heard the statement, "Once a cheater always a cheater" when I was in high school. Maybe some women are born with an innate desire to believe in the ability to change. I know I'm a little more evidence-based myself and if history is any indication, I'd say Don Draper will spend the rest of his fictional life appearing in the beds of women all over 1960s Manhattan.

Time heals all wounds, right? Wrong. If a couple who has suffered through infidelity does not properly recover and heal from it, time only makes the scar more visible. The wound may even re-open now and then. But if a couple uses time smartly, it can soothe the pain and the scar can begin to fade.

So, it's less than three weeks before Christmas. Friday night. Friends are winding down from their work week, decorating the tree with the kids, and maybe getting ready for a Christmas party. I just learned of my husband's affair. I picked up a card I found in his gym bag. I read the cover and thought, "Wow! This must be my Christmas card." But I didn't put it down, and the surprise was on me. It was from Karen. Karen? Who's Karen?

It's too easy to say that people cheat because they're unhappy in their marriage. I've observed that there are a number of reasons why people cheat, and these have everything to do with the character of the person cheating.