Imagine living in a parallel universe where everything was exactly the same as the universe we live in except that the socially accepted norm for marriage was homosexuality. Imagine that heterosexual marriage was frowned upon, and that the current civil rights movement involved trying to achieve marriage equality not for homosexuals but for heterosexuals. If you are among the very few who have homosexual tendencies, you might feel comfortable living in such a universe. If you are like the majority of people, though, you’d find that being a straight person living in a gay world would be very uncomfortable.
One could argue that heterosexuality is “normal” and that homosexuality is “abnormal,” since fewer than 10% of people are strictly homosexual and only about one third of people admit to being not exclusively heterosexual. One could argue that society’s preference for heterosexual marriage and its disdain or fear of homosexual marriage merely reflect the natural proclivities of the majority of the population. Equal rights aside, that seems like a perfectly reasonable and perfectly defensible position. The problem comes, however, when we apply the same reasoning to society’s preference for monogamy.