It’s generally not the random horniness or the “plain old nasty” when people wish and decide to have affairs. Affairs stem from the very fiddly aspect of our romantic psychology and lust may have very little to do with it. Watch this 3 minutes video essay on the reasons why we have affairs and why not to get too harsh with yourself or your partner since people almost never get into a relationship with the same needs for closeness or distance. In the end is openness, respect and understanding that keeps it all together.