Some of the stats are poorly phrased and you have to read to the bottom to get the low down:
https://www.reuters.com/article/us-usa-health-sex/young-u-s-men-having-a-lot-less-sex-in-the-21st-century-study-shows-idUSKBN23J2LI
Will social norms move towards polygamy as women compromise in exchange for security?