[drcube]

>The number of sexual partners adults have has been steadily rising

Got a cite for that? I was under the impression the opposite was true.

And even if it is the case, see the book "More Sex is Safer Sex" by Steven Landsburg:

"You’ve read elsewhere about the sin of promiscuity. Let me tell you about the sin of self-restraint.

Suppose you walk into a bar and find four potential sex partners. Two are highly promiscuous; the others venture out only once a year. The promiscuous ones are, of course, more likely to be HIV-positive. That gives you a 50-50 chance of finding a relatively safe match.

But suppose all once-a-year revelers could be transformed into twice-a-year revelers. Then, on any given night, you’d run into twice as many of them. Those two promiscuous bar patrons would be outnumbered by four of their more cautious rivals. Your odds of a relatively safe match just went up from 50-50 to four out of six."

https://slate.com/culture/1996/07/more-sex-is-safer-sex.html