Those of you who are men, or married, or women, or thinking of getting married, might find something interesting in today’s New York Times article about trends in infidelity:

• The lifetime rate of infidelity for men over 60 increased to 28 percent in 2006, up from 20 percent in 1991.
• The lifetime rate for women over 60 has tripled: to 15 percent, up from 5 percent in 1991.
• About 20 percent of men and 15 percent of women under 35 say they have ever been unfaithful, up from about 15 and 12 percent respectively.

Why is this? The theories offered are fascinating:
Viagra — “Among older people, a host of newer drugs and treatments are making it easier to be sexual, and in some cases unfaithful — Viagra and other remedies for erectile dysfunction, estrogen and testosterone supplements to maintain women’s sex drive and vaginal health, even advances like better hip replacements.”
In other words, they cheat because they can? Stated another way, the adultery rate had been artificially suppressed by men and women who would have happily cheated if they could have.
Internet porn — “In younger couples, the increasing availability of pornography on the Internet, which has been shown to affect sexual attitudes and perceptions of “normal” behavior, may be playing a role in rising infidelity.”
If true, this strikes me as significant. We all have a general sense that the rapid spread of pornography must have some social costs but it’s never been clear exactly what.
Instant Messaging — “Even for women who stay home, cellphones, e-mail and instant messaging appear to be allowing them to form more intimate relationships, marriage therapists say. Dr. Frank Pittman, an Atlanta psychiatrist who specializes in family crisis and couples therapy, says he has noticed more women talking about affairs centered on “electronic” contact.”
This strikes me as plausible and obviously not just for women. IM and email make it much easier to open up to strangers or people with whom you don’t or cant spend much time.
The article didn’t address this riddle: How could infidelity be going up while divorce rates are going down?
What are your theories?