In a new relationship, should you reveal how many people you’ve slept with?

Most people don’t want to know the number; studies say men typically have more partners.

In high school and through her early 20s, Lisa Mattson dated a lot.

Inevitably, after a few dates with a new guy, the topic of sex would come up. If her date asked how many men she’d slept with, Ms. Mattson says she would “act demure and avoid the answer at all costs.” Sometimes she took a sip of her beer to stall. If all else failed, she’d say she didn’t want to talk about it.

“I’d amassed a hefty number of ex-sex partners and I thought that scarred me for life as wife-worthy,” says Ms. Mattson, a 41-year-old director of marketing for a winery, who lives in Santa Rosa, Calif., and has written a book about her dating experiences, “The Exes in my iPod: A Playlist of the Men Who Rocked Me to Wine Country.”

It might be one of the most private pieces of personal information we have: our number of sexual partners. It is more than a number. It is a window into our relationship history and any conversation about it can be a moment when new couples get closer.

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Of course, sex educators, doctors and friends say to discuss it as part of practicing safe sex. And of course it isn’t easy to disclose.

In the Singles in America study published earlier this year by Match.com and conducted by a research company with several academics, just more than half of the 5,675 singles, ages 18 to over 70, surveyed said they didn’t want to know how many sexual partners their significant other has had. A 2006 study published in the Canadian Journal of Human Sexuality indicated that people who have had more sexual partners are perceived as less desirable for dating and marriage.

Many people are now dating when they’re older, so they’ve had more experience. And people’s numbers may differ quite a bit: Someone who is single in his or her 40s after being married for a long time will likely have a much lower number than someone the same age who was never married.

“Some people are concerned with being too far above average because it will make them look promiscuous; others are concerned with being too far below average because it will make them look inexperienced,” says Justin Lehmiller, a sex researcher and director of the social psychology graduate program at Ball State University in Muncie, Ind.

He adds that being too far above average tends to be a bigger concern for women, who are judged more harshly than men for having a more extensive sexual history.

No wonder that people often hedge when they’re asked how many people they’ve had sex with. A new study, published online in April in the Journal of Social and Personal Relationships, found that about 60% of participants had at least once failed to disclose their number of previous sexual partners to a current sexual partner.

The study, conducted by Sean Horan, an assistant professor in the department of communication studies at Texas State University, in San Marcos, Texas, surveyed 183 people—whose average age was 22—in Chicago and Austin, Texas, and found that the average number of sexual partners they’d had was eight. (The results weren't broken down between men and women.)

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Dr. Horan asked participants if, before engaging in sexual intercourse, they’d ever told a new partner about the number of people they’d previously had sex with.

And he asked if they’d ever withheld this information from a new sexual partner. He found that about 40% of participants never omitted their sexual history (meaning number of partners); 40% omitted disclosing their sexual history to at least one partner, and 20% omitted disclosing their sexual history to all partners. The individuals with the highest number of sexual partners disclosed their number less often.

Dan Nainan, 33, a comedian who lives in New York City, says that pretty much every girl he dates gets around to asking him how many sexual partners he’s had. He tells them he’s “averaged about two a year.” He doesn’t mention that he’s amortizing his number starting at birth. “It sounds a lot better than saying, ‘I’ve slept with 70 women,’” he says.

So what’s a normal number? Researchers don’t always agree, in large part because they ask about sexual partners in different ways or use different samples, and study participants have varied views on what constitutes sex. The National Survey of Family Growth, conducted by the Centers for Disease Control and Prevention and surveying more than 13,000 individuals ages 15-44 between 2006 and 2008, found that the median number of female sexual partners in a lifetime for men ages 25 to 44 was 6.1 and the median number of male sexual partners for women of the same ages was 3.6.

The Singles in America study published this year tallied up men’s reported average of lifetime sexual partners at 14.64 and women’s reported average at 8.41.

The Centers for Disease Control and Prevention study indicated that women were more likely to report having only one partner, and men were more likely to report having had more than 10. Experts believe that the men and women may have been defining “sex” or “sexual partner” differently.

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Or it may be that women underreport and men overreport. A 2003 study published in the Journal of Sex Research found that when men and women were connected to a device that they believed was a lie-detector (but, in reality, wasn't), the differences between the sexes in the number of sexual partners became much smaller.

Intimacy and trust, of course, are needed to discuss the number. It can help to frame it in the context of a general conversation about sex, researchers say. Frame the talk as caring and safety-oriented, Texas State’s Dr. Horan says. Explain that you are with your partner because of who he or she is now, not before you met. And show that you feel vulnerable, too: “Just as you have a past, I have a past.”

As Ms. Mattson approached 30, she started to realize that avoiding the sexual-history talk was leading her to make poor choices in partners—she was ending up with men who just wanted sex, not a relationship.

When Ms. Mattson met her now-husband, 11 years ago, she dated him three to four times a week for a month before she had sex with him. During that period, her sexual history—and his—came out gradually, in stories. She told him about some of the men she’d dated and what she’d learned. (Her husband declined to comment.)

“It wasn’t necessarily a conversation about a number, but I was much more confident and talked about how I’d made mistakes,” Ms. Mattson says.

“I got to know him better before I slept with him than any man before,” she says. “And he loves me for who I am.”

Neither has divulged his or her number.

This article was originally published on 04-05-2015 on The Wall Street Journal

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