Divorce is worse for everyone involved, he argued. Economists have found that children raised by divorced and unwed mothers don't do as well in school and make less money when they enter the workforce.
From Biderman's point of view, infidelity is just a way to keep families intact.
"It's a life preserver for their marriages," he said.
Assessing this claim is difficult. Reliable data on families in which a parent has been unfaithful are difficult to come by, since people have no reason to be honest with surveyors about whether or not they've cheated. Estimates of how many marriages are betrayed range from a small fraction to the vast majority, and it is difficult to know how infidelity affects those marriages.
In some cases, infidelity might result in divorce. In other cases, infidelity could be the symptom of deep unhappiness, even physical violence, between spouses, and divorce could be the best among bad options for the family as a whole.
Many therapists believe that marriages can generally be rescued, including Scott Haltzman, a psychiatrist and an inveterate opponent of Ashley Madison who has refused to speak with the press about the site for years to avoid giving any ideas to readers who may be considering an affair. He talked to Wonkblog Thursday morning, saying the hack would likely deter any new customers.
"I think people just give up too quickly," Haltzman said. "Sometimes, that's all I have to do when I meet with a couple, tell them, 'Your problems are solvable.' " In his book The Secrets of Surviving Infidelity, he estimates that more than half of married couples in which a partner strays do not end in divorce - an estimate he acknowledges is uncertain.
He and other psychologists rely on personal experience with couples who come into their offices. Every family is different, and the families who tend to participate in therapy or who volunteer for studies might not be representative of families in general.
Haltzman agreed that monogamy might not be natural for humans in an evolutionary sense, but, he noted, humans avoid many behaviors that might have made sense for our prehistoric ancestors interested in passing on their genes, such as theft and violence. Infidelity has costs for children, he argued. Those who stray spend less time at home with the kids, and less time working to preserve their marriages - even if the cheater is never found out.
Even Biderman agreed that infidelity was bad for a marriage if the spouse learns the truth. That, he said at the time, was rare.
The discovery of an affair "comes with a whole host of consequences," he said. "Most of it never gets discovered."
