I don’t think they’re a huge amount of people, at least currently. It looks like about 30% of Americans between 25 and 50 have never been married. That means at least 70% of that group has been married, more will marry in their lifetimes, and likely a large amount of people fornicate out of wedlock.
That indicates that the vast majority of people has at least one sexual partner, with many having a lot more thanks to sexual liberation.
For the record, I’m not saying that this is a bad thing at all. I was just alluding to the fact that we can’t compare life and expectations of safety to what it was even 100 years ago, let alone over “millions of years”
Many people can go their entire lives having the internet as their sole partner.