Why many of us show interest on extramarital contacts irrespective of age/gender

Greetings :) I believe there is a very simple explanation for this. It simply is that you or your spouse is not happy. If you are happy, you wouldn't cheat on your girlfriend/boyfriend/partner. If you want a more complicated explanation: it is the psychology of it. The fact that something is wrong, makes you more and more prone to doing it because, we are curious and rational beings. Someone tells you not to look in the cookie jar, there is a likelihood that you will because, you would wonder what is being hidden there and what is wrong of looking inside it. Cheating in itself is a form of rebellion and I guess this is why people do it. If your mom tells you not to see a certain guy, you might do it if you had a really bad fight with her. Basic things do lead to this. I guess we all should just find a way to control ourselves as mature individuals in society.