Stephanie Coontz is Director of Research at the Council on Contemporary Families and teaches history at The Evergreen State College in Olympia, Washington. Her most recent book is "A Strange Stirring: The Feminine Mystique and American Women at the Dawn of the 1960s."

...President Thomas Jefferson fathered a child by his mistress. So did Warren G. Harding, who also carried on an affair with the wife of a family friend. Gen. Dwight Eisenhower had a long-term relationship with the woman who was his driver in England during World War II. CIA Director Allen Dulles, according to his own sister, had "at least a hundred" affairs, including one with the queen of Greece. President John F. Kennedy's affairs and one-night stands may have numbered even more.

But times have changed. The press and political insiders no longer turn a blind eye. So why do men continue in behaviors that now carry so much risk of exposure and punishment?...

Today many -- perhaps most -- men sincerely want to marry women who are partners rather than subordinates. And women now want careers of their own, whether paid or unpaid, rather than defining themselves entirely through a husband's achievements. Yet many of our romantic fantasies and cues for sexual arousal are still shaped by the unequal division of roles, power, resources and prescribed character traits that prevailed from the early 19th century up through the 1960s....