A recent high-profile extramarital affair has prompted New York Times to take a closer look at the institution of marriage — and what it finds might surprise you:

Despite strong social riptides working against it — the liberalization of divorce laws, the vanishing stigma of divorce, the continual online temptations of social sites like MySpace or Facebook — the marriage bond is far stronger in 21st-century America than many may assume. Infidelity is one of the most common reasons cited by people who divorce. But surveys find the majority of people who discover a cheating spouse remain married to that person for years afterward. Many millions more shrug off, or work through, strong suspicions or evidence of infidelity. And recent trends in marriage suggest that the institution itself has become more resilient in recent years, not less so.

“Every marriage has many, many more dimensions to it than faithfulness,” said Betsey Stevenson, an assistant professor of business and public policy at the Wharton School at the University of Pennsylvania who studies marriage and divorce trends. “We don’t see the other sacrifices or other betrayals of promises. I wonder if faithfulness really is a litmus test in marriages, or if it just becomes a litmus test in the media because that’s the one betrayal we hear about in these celebrity relationships.”

Historically, the institution of marriage has not succumbed to infidelity so much as coexisted with it, like a body does with the flu virus: weakening at times, yet developing some immunity from long exposure. Anthropologists have found patterns of infidelity in diverse communities around the world, just as historians and novelists have. Many men and women, and most visibly men, have long been “publicly monogamous and hidden their affairs,” as the anthropologist and writer Helen Fisher of Rutgers University has said.

Temptation stalks even close marriages, as researchers have had no trouble documenting it. In one survey, psychologists at the University of Vermont asked 349 men and women in committed relationships about sexual fantasies. Fully 98 percent of the men and 80 percent of the women reported having imagined a sexual encounter with someone other than their partner at least once in the previous two months. The longer couples were together, the more likely both partners were to report such fantasies.

In another study, psychologists at the University of Washington and the University of North Carolina reported that married men and women who called their relationship with their spouse “pretty happy” were twice as likely to cheat as those who said their relationship was “very happy.” But perhaps the strongest risk factor for infidelity, researchers have found, exists not inside the marriage but outside: opportunity.

“People tend to assume that bad people have affairs, and good people don’t, or that affairs only happen in bad marriages,” said Peggy Vaughan, a San Diego-based researcher who runs the Web site dearpeggy.com, and author of a forthcoming book on infidelity and marriage, “To Have and to Hold.” “These assumptions are just not based in reality.”

In any given year, about 10 percent of married people say they have had sex outside their marriage. These numbers say nothing about whether the affairs were discovered; but researchers have surveyed couples in which they were. In one survey, among 1,084 people whose spouses had affairs, Ms. Vaughan found that 76 percent of both men and women were still married and living with that spouse years later. Similar surveys have found rates of about two-thirds and higher.

Check out the link for more.

PHOTO: South Carolina Governor Mark Sanford and his wife Jenny.