Is sex once a week enough for a happy relationship?

We live in a society where sex is often touted as the secret sauce that keeps a relationship tasty. So more sex must be better for you and your romantic partner, right?

Well, for established couples, having sex once a week hits the sweet spot for happiness and well-being, a study finds. This is either great news or tragic, depending on how you're feeling about your sex life.

It turns out that psychologists are working hard to figure out whether more sex makes us happier.

Researchers looked at data on 25,510 Americans, ages 18 to 89, about two-thirds of whom were either married or in a romantic relationship. For the people married or in relationships, more sex definitely correlated with more happiness. That wasn't statistically significant for the single people not in a relationship.

But when the researchers crunched the numbers to find out if there's an upper limit to improving well-being through sex, they found that the happiness maxed out at sex about once a week.

"This showed a linear association between sex and happiness up to a frequency of once a week, but at higher frequencies there is no longer an association," Amy Muise, a social psychologist at the University of Toronto Mississauga who led the research, said in an email. "Therefore it is not necessary, on average, for couples to aim to engage in sex as frequently as possible." The results were published Wednesday in the journal Social Psychology and Personality Science.

OK, but the data come from U.S. surveys done in 1996 and 1998, years the researchers picked because those sets of data had information on both marital status and relationship status. Surely things have changed on the relationship front since the Clinton administration?

To answer that question, Muise and her colleagues also gathered data from a much smaller ethnically diverse group of people online. Those 355 participants also tended to be happier as frequency of sex increased. But the happiness leveled off with sex more than once a week.

To make it more interesting, the researchers also compared whether having more sex made people happier than having more money. It turned out that these people think having money would make them happier than having sex. But sex won out over money in that apparently magical once-a-week spot.

This suggests that John Updike was wrong when he wrote: "Sex is like money; only too much is enough."

Still skeptical? The researchers also used a third national data set that looked at happiness, sex and relationship satisfaction, and found that frequency of sex accounts for just 7 percent of the association between relationship satisfaction and happiness.

By now you may have thought, "Oh, it's different for men." But the researchers found that the once-a-week correlation held steady regardless of people's age, gender or length of relationship.

This suggests that Woody Allen was wrong when he wrote this immortal scene in Annie Hall:

Alvy's therapist: How often do you sleep together? Annie's therapist: Do you have sex often? Alvy: Hardly ever. Maybe three times a week. Annie: Constantly. I'd say three times a week.

If you're still concerned about discrepancies between the findings and your own experience, don't fret. These studies merely find associations in large groups of people and can't prove a sexual cause for a given happiness effect.

Also, what emerges from the group doesn't trump your personal experience. You can go on doing what works for you and your honey. The take-home message, Muise says, is that it's "important to maintain a sexual connection with a romantic partner, but it is also important to have realistic expectations for one's sex life (given that many couples are busy with work and family responsibilities.)" Copyright 2019 NPR. To see more, visit https://www.npr.org.