Married couples are less likely than other couples to fight about jealousy - but when they do, it's much more damaging, researchers at the University of British Columbia and the University of Iowa have found.
Their study showed that without jealous conflict, three-fourths of the married individuals surveyed were extremely satisfied with the emotional aspects of their marriage.
However, the chances of having that same level of satisfaction dropped to less than half if jealousy entered the equation.
For unmarried cohabiting couples, the probability of being highly emotionally satisfied only fell about eight points with jealousy. A similar contrast was observed for physical satisfaction.
"We associate certain rewards with marriage, but there are risks to it as well," said Anthony Paik, assistant professor of sociology in the UI College of Liberal Arts and Sciences.
"The advantages to marriage include deep commitment and trust. But when jealousy occurs in a marriage, that tension can have devastating effects on emotional and physical satisfaction. It's not a straightforward story that marriage produces happier relationships," he added.
Paik along with Mariana Gatzeva of the Department of Human Kinetics at the University of British Columbia analyzed a survey of 681 heterosexual men and women in marriages, cohabitant or non-cohabitant relationships from the Chicago area.
Participants answered questions about whether they had experienced sexual jealousy and their level of physical and emotional satisfaction with their relationship.
More than half of cohabiting individuals reported sexual jealousy, compared to about one-third of individuals who lived separately (such as dating couples), and just 18 percent of married individuals.
Paik said the high rate of jealous conflict among cohabiting couples could be due to a strong expectation of exclusivity but less fidelity.
Researchers believe married couples encountered less jealousy because of the sexual exclusivity that goes along with exchanging vows-but also because they were more trusting.
"There may be a set of beliefs that's protective for married couples in terms of avoiding jealous feelings. They're somewhat insulated because they're more trusting, and therefore less likely to be suspicious or look for breaches," Paik said.
Paik said understanding intimate partner jealousy is important because it could be useful in preventing domestic violence.
"Jealousy is a very powerful emotion. In many cases, jealousy or love triangles are the motive for homicide or other violent crimes between intimates," he said.
The study has been published online in the Journal of Sex Research.