All of our romantic stories are about two singles meeting and marrying, but 2/5 times, at least one of them has already been married at least once.
Meanwhile, 25% of over-40 year-olds have never married and most of them are living alone.
Typical for polygamous societies is a high never-married rate, especially amongst men, and that's what we're seeing.
Tired of being seen. Just want to soak my way into single 40s 
According to Joseph D. Unwin who 1934 published a book called "Sex and Culture" dealing with the correlation between a society's level of "cultural achievement" and its level of sexual restraint.
His study of 80 cultures throughout history led him to the conclusion, that as cultures/societies develop, they become more sexual liberal, which leads to a loss of cohesion, impetus, and purpose. What inevitably follows is the succeeding decline of this culture/society.
He was probably thinking about Berlin.
