I stumbled upon a video where author Melissa Margaret Schneider talks about her book The Ugly Wife is a Treasure at Home: True Stories of Love and Marriage in Communist China. The saying comes from a Chinese custom where men who are on the lower end of the socioeconomic status ladder tend to marry unattractive women because they're easier to obtain, so to speak, and they marry them not necessarily because they're in love with them but they want to have a family and carry out their family legacy. An attractive woman is seen as a risk because attractive women are seen as materialistic and more likely to leave their husband for a more attractive man who gives them attention.
The author also talks about the concept of "leftover women". I've heard about this phrase before and it basically means that if a woman's "expiration date" when it comes to marriage is 27, and according to the author, a high percentage of men in China believe that a woman is not worth marrying if she's older than 27, which is problematic to say the least. To an extent, I believe American culture is similar because society romanticizes youth, especially if you're a woman. People still think a woman's life is "over" when she reaches the age of 30, despite all the "[insert age] is the new [insert age]" sayings. An older man who isn't married isn't stigmatized the way that an older unmarried woman is.