My wife is from Beijing. She is 39, and lived through the cultural revolution in Beijing.
During that period, many were taught that sex is "dirty", and not good for "ying, and yang."
She has NEVER liked sex in her lifetime, but she disagrees.(Like of course, is subjective.) She complains that before, and after sex, tired.
Before we were married in 2000 she promised she would "change" after we married. We married. In four years she, and I had sex FOUR times.