You raise a very interesting point. It would seem, theoretically, that this
would indeed be the safest form of sex: being with only one partner, exclusively.
And, I am not saying that there is no value in this, but it is not
straightforward as it may seem.
The reality is that having sex with only one partner, in and of itself, is not
a guarantee of safety. Think about it: you are better off having sex with 1000
people who don't have a sexually transmitted disease than one who does. In fact,
a famous research study examined this very situation. Using a statistical model,
it was found that you are indeed safer having sex with numerous people using
safer sex than one person minus safer sex.
Your model is based on a couple of assumptions: 1) both people have either
never had sex with anyone else or they have both been fully tested for all
STDs; and 2) neither partner ever has sex with anyone else. Unfortunately,
this is more tricky than it sounds. Research shows that over 50% of people
will have an affair at some point in their lives. Even more disturbingly, over
90% of both men and women admit that they aren't entirely honest about their
sexual history with new partners. In fact, people are so likely to lie about
their sexual past that the Centers for Disease Control years ago stopped
recommending asking a partner about their sexual history. In some ways,
asking can be considered a form of unsafe sex because it lulls people
into a false sense of security. You are much better off engaging in what is
known as "universal precautions" -- being safe no matter what.
During my stint as an HIV researcher, I noticed one particularly scary pattern:
people would often begin having safer sex with a new partner, then switch to
unsafe sex after a few months. Of course, they wouldn't get tested before this
switch, they simply would feel that they now "knew" this person well
enough. Knowing a person, or being together for a long time, is not a form of
safer sex.
So, unless you are absolutely certain that you and your partner are
completely monogamous, and you have both been tested for all STDs, stick with
condoms. Thanks again for you letter.
