As recent as the 17th century, polygamy was practiced and accepted by the Christian Church. Monogamy was introduced into Christianity at the time of Paul when many revisions took place in Christianity. In the American society many times when relations are strained, the husband simply deserts his wife. Then he cohabits with a prostitute or other immoral woman without marriage. Islam condones but discourages the first and forbids the other two.
Wars cause the number of women to greatly exceed the number of men.
In a monogamous society these women, left without husbands or support, resort to prostitution, illicit relationships with married men resulting in illegitimate children with no responsibility on the part of the father, or lonely spinsterhood or widowhood. Some Western men take the position that monogamy protects the rights of women. The society has so many practices which exploit and suppress women, leading to women's liberation movements from the suffragettes of the early twentieth century to the feminists of today. Easy birth control and easy legal abortion has opened the door of illicit sex to women and she has been lured into the so-called sexual revolution. But she is still the one who suffers the trauma of abortion and the side effects of the birth control methods.