4. Don't have this conversation in bed—or anyplace you associate with intimacy
Although this is a good guideline to follow when dealing with all types of relationship secrets, there's only one instance in which it is a hard-and-fast rule, Sussman says: "Don't wait until you're naked in bed with someone to tell them you have an STD."
That's true for any condition, Davis adds. But Dr. Robbins notes that if your health secret is a sexually transmitted disease (STD), you're going to have to open up to someone sooner rather than later.
"If it's something that's going to have a direct effect on your partner, it's something you're going to want to talk about sooner, as opposed to an illness that isn't contagious," Dr. Robbins says. "If it's something like hepatitis C, you really do have to talk about that very early."
Amy, a 29-year-old graphic artist from Chicago, jokes that hepatitis C is the only thing she has in common with Pamela Anderson. But she's serious when it comes to telling boyfriends about her illness, which she got through a blood transfusion at birth.
"There is less than a 3 percent chance of transmission within a monogamous relationship, but I've always been truthful and upfront about it, whether I ended up in a sexual relationship with someone or not," she says. "They have a right to know."
An ideal place to tell someone about your health secret—whether it's a communicable disease or any other condition—is a park, Davis says. Just make sure there's no one within earshot.
"Do not tell your partner during intimacy. Telling your partner your health secret means you are opening up to them, trusting them, and becoming more vulnerable," she says. "The place you choose to tell them should reflect this."