Morality of Mankind: Extramarital Affairs

91% of Republicans think extramarital affairs are immoral, while only 78% of Democrats would agree. Independents are in the middle at 86%, according to the Pew Research Center's Spring 2013 Global Attitudes survey. Divorce appears to be far more permissible, as only 37% of Republicans and merely 17% of Democrats think divorce is morally unacceptable.

So then, where do people get their sense of morality from?

Libertarians laud their policy of "don't harm others" as paramount for society to exist, which is not far from Google's motto, "Don't be evil." Yet extramarital affairs cause great amounts of pain and hurt to the spouse who has been cheated. According to this framework, affairs would be immoral. 

People who have a relationship with God or follow religious tenets are among the highest who disapprove of affairs. For example, Christians believe that God created the universe and established principles of behavior that are for the good of society, such as not stealing, coveting, lying, or being unfaithful in marriage. 

Maybe these 9%, 22% and 14% of people see no moral problems with affairs because they themselves are in affairs or have been involved in affairs previously. Would they still think there's no moral problem with it if their spouses were the ones in the affairs?