Call it sexual history poker: You have each slept with an unknown number of people. When it comes time to share, do you bluff, fold or lay your cards on the table? 

The decision to share the 'magic number' of sexual partners almost always comes up between couples, experts say, but divulging too much detail often causes hurt feelings, jealousy and worse. 


Honesty Overdose 

Therapists generally say truthfulness between couples builds trust, but every expert interviewed by FOXNews.com said the number of sexual partners was one area where full disclosure is not a good idea. They don't recommend lying, but argue the sexual body count can sometimes remain unsaid. 

"The perception that couples should share everything is itself a misconception," said sex therapist Isadora Alman. "People need to keep some part of their lives private." 

 
'The perception that couples should share everything is itself a misconception. People need to keep some part of their lives private.' — sex therapist Isadora Alman 
 

Of course, keeping your past sex life private sounds fine in theory, but in the real world it can be difficult and awkward: declining to share the sensitive info makes it look like you have something to hide. 

"I never ask how many, but some women always want to know how many others I've slept with," said Anthony, a 29-year-old New Yorker. "I figure, what difference does it make now? I'm HIV- and STD-free and I'm treating you all right, so why stress yourself out with numbers?" 

The Need to Know 

People are driven to uncover their lovers' sexual history by a combination of concerns: sexually transmitted diseases, jealousy and insecurity. 

That is why sharing information on the number of partners can be harmful — especially when there's a big disparity, Alman said. Once the sexual history deficit is exposed, "the only way around it is for one person to go outside of the relationship to catch up — not usually a good option."

 
'I'm HIV- and STD-free and I'm treating you all right, so why stress yourself out with numbers?' — Anthony 
 

Then there's the issue of gender politics. Some women may feel the need to under-report the number of sexual partners, while many men are less likely to do so. 

"Women are much less willing to divulge the true number of partners because they still suffer from the Victorian concept that nice girls don't [have sex]," said Dr. William Fitzgerald, a sex therapist at the Silicon Valley Relationship Center. "Women and men alike should ask, 'Why do you want to know? What would a high or low number mean?' " 

Such attitudes can quickly rule out honesty as the best policy. "My boyfriend and I have almost broken up over this a bunch of times, said Sofia, a dancer from Miami. "He cares about my number, but he'll never know, because I know that he has a certain idea of how women should be. With guys, you just assume they sow their oats, but people expect women to come off as chaste." 

Love in the Time of HIV 

Even concern about sexually transmitted diseases doesn't qualify as a valid reason for full disclosure. For example, a long-term, unsafe-sex relationship with an HIV-positive partner is more dangerous than a slew of safe-sex one-night stands. Therefore, people are much better off asking if their partner has had unsafe sex or used intravenous drugs instead of relying on their number of partners to gauge risk. 

 
'With guys, you just assume they sow their oats, but people expect women to come off as chaste' — Sofia 
 

"If a guy has had only one sex partner but they were a junkie, then [the low number] is misleading," Fitzgerald said. 

Then there are those who think there's a "correct" number — and are eager to make sure their tally matches up. "Some people want to know what the average number [of partners] is," said Alman, "and although there have been studies, I try to steer them away from that question." 

The most recent data, from the National Health and Social Life Survey completed in the mid-1990s, found the median number of partners for men was six and for women, two. But measuring your sexual history against an aggregate statistic, she argued, is not a good idea. 

Keeping it Vague 

If you absolutely have to tell your partner something, the best route is to keep your answer vague, according to the relationship experts interviewed by this reporter. "You find a way of being honest without injuring the feelings of your partner," said psychologist Dr. Dorothy Strauss. 

For example, you might tell your insistently curious lover you've had more or less than five partners. "Say 'Yes, I've been with more than five lovers' and leave it at that," Fitzgerald said. Any more information than that is probably overplaying your hand.