But that's not what the assertion is, so how about we stick to the facts related to that and not other tertiary suppositions?

And although a man biologically could and some do impregnate several women in a 9-month period, it's still unbelievably uncommon for all of the reasons that I named in the OP. For starters, most men have the same average number of partners as most women in a year - around 1 and the number of lifetime offspring for men is only slightly higher than for women.

https://www.mindbodygreen.com/articles/the-ideal-number-of-sexual-partners-for-men-women#:~:text=A%202017%20survey%20of%202%2C180,average%20of%208%20sexual%20partners.

"According to 2011 to 2015 CDC data1, women between ages 25 and 44 had a median of 4.2 sexual partners, while men in that age group had a median of 6.1 sexual partners. (These are medians, not averages. These medians are based on number of lifetime sexual partners among sexually experienced men and women, meaning they don't take into account people who have had zero sexual partners.)"