COMMITMENTS : How Much Is Too Much to Tell? : There’s a delicate balance in talking about your sexual history with a new partner. So think twice before you speak.

You’ve known each other for a while and built up some trust and you think it’s time to let your partner in on your past. Your . . . uh . . . sexual past.

Perhaps there is some promiscuity there, maybe an abortion or rape or incest. It could be that you and your last partner enjoyed some rather kinky sex or that you were once treated for a venereal disease.

How--and how much--should you tell?

“There is a delicate balance of what needs to be kept private and what needs to be shared,” said Christine Leon, an educator with the student health service at UC Irvine and former coordinator of the school’s rape prevention program.

While everyone has a responsibility not to put a partner at risk of AIDS or other sexually transmitted diseases, experts agree that you have a right to maintain privacy about other matters.

Before you tell all, they advise, consider how much information your partner really wants and can handle, and evaluate your motive for sharing. Too many details about past lovers could push your current partner’s jealousy button.

“It is not appropriate when you’re beginning to date someone to give them your whole sexual history. That can be overwhelming,” said Ken Unmacht, a marriage and family therapist in Brentwood.

Personal information is more naturally shared as trust and commitment grow over time, Leon said, and a couple should wait until then to become sexually involved.

“You cannot determine what is (physically or psychologically) safe until after a period of time when you know the level of trust is high and you know the information is full and honest,” she added.

In sharing some information, one might risk losing a mate’s respect or even the relationship itself. The risk is the same whether the tidbit just slips out or is revealed in the name of honesty.

Valerie Gold-Neil, a psychologist in Laguna Beach and executive director of the nonprofit HIV Women’s Voices, knows this professionally as well as firsthand.

She said she is very upfront with a new partner about her sexual past “because it’s a part of who I am. It has formed my life and made me stronger in many ways.”

Gold-Neil said she was sexually abused by her father, raped, had two illegal abortions and put a child up for adoption, all before the age of 18. She was later married for 10 years and had a son.

“It’s hard to tell somebody all of this. I wonder if they’ll ever believe all this happened to one person and how they’ll accept or not accept that or how they will judge. But most women are very accepting,” said Gold-Neil, who is in a lesbian relationship.

Some people hesitate to discuss past sexual abuse unless it is affecting a current relationship. When the subject is broached, they only hope their disclosure will be met with empathy and understanding.

But there is never a guarantee; it can end a relationship before it began or spell the end of a marriage.

This can happen even with a seemingly innocent remark that triggers a partner’s insecurities, said psychologist Michael S. Broder, author of “The Art of Staying Together” (Hyperion, 1993).

Broder recalled a woman who mentioned to her husband of three years that 10 years earlier, in college, she had been treated for crabs.

“He couldn’t handle it,” Broder said. “He was terribly insecure.”

The downward spiral began as the husband, unable to stop envisioning his wife with people who had diseases, lost his desire for her. This led to other problems and they ended up divorcing.

“She believes with all her heart and soul that, had she not told him, the marriage would (have been) OK,” Broder said.

Other people can hear information, even details about past lovers, and be very accepting. The key is knowing your mate.

“Alice,” who is in her late 30s, said it did not bother her to know that her husband had had a series of one-night stands before they married 14 years ago. Even hearing the details of one that occurred on the eve of their wedding didn’t faze Alice, who described herself as confident.

Past lovers, however, can be a touchy subject for the insecure--including many men. The topic, Broder said, does not need to be discussed unless it enriches your sexual relationship.

“Some people--I hear it from men more--find the thought of their wife having been with someone else devastating, even though they may know it occurred,” Broder said.

This is also true for men who are dating. Said “Marvin,” a 34-year-old Los Angeles dentist: “I don’t want to know the particulars: how many men, who they were, how emotionally tied she was to her former sexual partner. I don’t want to torture myself with the emotional swings of her past history.”

“Teresa,” a 57-year-old teacher from Thousand Oaks, said this is even more true for older men.

“They don’t want to hear about anyone else even if they know you were married and then single for a number of years,” said Teresa, who was married for 17 years and has been single for the last 18.

“You don’t volunteer information or they look at you like a wanton woman,” she added.

But a person can still be honest and not reveal everything, from a rape to the fact that he or she slept with half the track team.

One way to honestly handle an uncomfortable question is to say, “I’d rather not talk about that right now. Maybe I can go into it at a later date, but I’m not comfortable with that right now,” Unmacht suggests.

For after all, Broder said, “your past belongs to you.”