Thanks for an excellent article. I’ve always been amused by the cry of “It can’t last!” in a society where half of all marriages end within 5 years.
One thing you didn’t mention is that quite often intelligent & mature young people are bored senseless by potential partners of their own age, who seem immature and shallow. So they seek out older (male, female, whatever) romantic partners because they need more emotional and intellectual connection than is available from the typical person of their own age.
As for sex, given that the average US male at 30 is already flabby and unhealthy, a fit 50-year-old can probably out-perform him across all types of activity…