Absolutely, it's a horrible thing to contemplate. As a single man who is not very successful with women, I'm equally afraid of this outcome as I am of being alone forever. Perhaps even more.

I would love to find a way of coming to terms with this that doesn't involve adopting the full red pill attitude of "never get married, all women are like that" etc

On the positive side, this probably means that the average man will marry a woman in the top50% of the romantic relationships he has had in the past. So you can focus on that thought. :)

Of course, this is possible because the average man will have far fewer relationships than the average woman. So in the end the numbers for this imaginary couple will look like:

For the man: He will marry then number 2 mate out of a total of 5.

For the woman: She will marry the number 10 mate out of a total of 15.

Obviously the numbers are totally made up, but you get the point.

So be positive! When you will settle, your mate will probably exceed your expectations.

Disclaimer: I am also a man.

It’s interesting that girls start at the top and get rejected down to their compromise level. Men start at the bottom and rise up to catch the falling girls. I am not sure either is better off or worse. Also you can look at other things... rank people on ability to cook, sing, solve puzzles, money, humor, cleanliness, optimism, generosity. Also even if you are hung up on number of or looks of mates, you can lower your standards, pay for it...

Best is to find your own self esteem. Whoever gets your company and attention is lucky, because you chose to give it to them and no one else...

It’s just you in the Boltzmann brain... no one else means anything. Also the universe is big, really big. And the block universe is here all at once. You can’t really change anything... we don’t know anything. What were we talking about again ?