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But the wild emotions of passion have an intoxicating effect on the brain. Mr. Haidt compares passion to an addictive drug. It impedes our ability to think and act clearly. Like cocaine, its symptoms include giddiness and euphoria. And, following the high, there is the inevitable feeling of disappointment and withdrawal: The passionate stage of a relationship lasts only 18 to 24 months.

Once the passion fizzles out, many relationships end because a hiatus in passion is “taken to mean an end to the love,” explains historian Stephanie Coontz, author of “Marriage, A History: How Love Conquered Marriage.”

Couples should look instead to companionate love as the source of true marital happiness, Ms. Coontz advises. “Marriages founded on passion are much less successful than ones founded on companionship, mutual respect, shared interests and real enjoyment of each other’s company,” she says.

John Gottman, a psychologist at the University of Washington in Seattle and a leading marriage scholar, confirms that friendship is the most important factor in keeping a marriage together. Scientifically studying the habits of hundreds of couples in his “love lab” over the years, Mr. Gottman found that the most successful ones spend five extra hours per week on their marriages. That doesn’t necessarily mean weekly candlelit dinners. It can be something as simple as holding hands while you recap your day at work.

“Romance is fueled by a far more humdrum approach to staying connected,” Mr. Gottman wrote in his 1999 book “The Seven Principles of Making Marriage Work.” “It is kept alive each time you let your spouse know he or she is valued during the grind of everyday life.”

“Our whole model of marriage is flawed,” Mr. Epstein declares, citing the high divorce rates in the U.S., where 50 percent of first marriages fail, 67 percent of second marriages fail, and 73 percent of third marriages fail. Rather than look west to Hollywood for a marital ideal, he proposes we look east to India.

In Eastern cultures, where conventional wisdom holds that “first comes marriage, then comes love,” arranged marriages rely on compatibility to work, and often serve as a bulwark against the vagaries of passion.

“There is another model for us,” says Mr. Epstein. “It’s not to practice arranged marriages, but it’s to learn from them.”

In a study published by a peer-reviewed journal of psychology in 2008, marriage researchers Jayamala Madathil and James M. Benshoff studied Indian couples living in the United States and found — brace yourselves — that those in arranged marriages were substantially more satisfied with their relationships than those in “choice” marriages.

A 1982 study published in India by psychologists Usha Gupta and Pushpa Singh goes further. When the researchers looked at the love in arranged marriages, they determined that the love started out very low and then increased over time. In love marriages, by contrast, the love started out very high and decreased over time. By the five-year point, the love in arranged marriages surpassed the love in love marriages. Ten years into the marriage, the love in arranged marriages was twice as strong as the love in love marriages — a shocking reality for Americans, who have an expectation that freedom in all matters, especially in love, will make them happier.

Mr. Epstein mentions a Pakistani woman he interviewed who was in an arranged marriage. When he asked her to rate the intensity of her love on a scale of 1 to 10 on the day she was married, she said it was a 0. How in love was she now, he asked? An 11. She and her husband have been married for 45 years.

This isn’t to dismiss passion. Psychologist Arthur Aron at New York’s Stony Brook University is among those who stress that companionate love and passionate love aren’t mutually exclusive and that the most successful couples are those that share both. Mr. Aron and his colleague Bianca Acevedo studied the brains of people who claimed to be madly in love with their spouses after an average of two decades of marriage. They found that two areas of the brain were lit up — the area associated with dopamine activity (passion) and the area associated with pair bonding (friendship).

Even “a companionate marriage can founder if a couple doesn’t find some way to ignite such sexual attraction and keep it burning, even if it stays on the back burner for days at a time,” allows Ms. Coontz.