Today I would like to share an interesting but sad reportage about the  concubine "system" that had been rampant in old society of China, especially within the families among warlords, lanlords, or even some intellectuals.  Biologically speaking, the ratio between newborn boys and girls is 106:100.  In other words, the equilibrium will be further enlarged if many grown males possess more than one wife, that will definitely widen the existing social inequality.

Under the law of monogamy, now mistresses have replaced concubines in either side of the strait and gradually become a "public hazard" to normal families.  Well, a guy is a guy.  As that famous movie star Chen Long once said that he "commits the error which (most of) males are liable to do", at least wealthy and powerful men are prone to temptation from women, being either dignified and liberal in the past or on the sly nowadays.    

https://www.toutiao.com/a6712655687245103630/

PS  Though I think men should keep themselves away from the women other than their spouse, still I believe some men are "永恆而不專一" emotionally.