The US is not “puritanical”. I wish it were.
This “puritanical” meme is so stupid.
You are right.
The average American has over 8 sexual partners in the course of his or her lifetime. However much one may want to twist this, it isn’t much different from polygamy, adultery and infidelity, all rolled into one. Hypocrisy is rife with regard to sexuality, here.
Sex after marriage is a mythical concept in American society.