What wikipedia has to say about Monogamy.


What now, Monogamy

Unnatural

Many authors criticize lifelong sexual monogamy as unnatural and unrealistic. They contend that humans have never been a sexually monogamous species, and that cultural expectations of sexual monogamy place enormous burdens on individuals to fulfill all the sexual needs of their partners. These expectations are quite unrealistic given how much variety exists in people’s sexual desires and sex drives. In addition, sexual desires and sex drives can change over time due to circumstances (e.g., periods of high stress or poor health) and due to normal aging (e.g., changes in hormonal levels). Loving partners can find themselves mismatched in terms of their current sexual desires or sex drives. The failure to live up to unrealistic expectations of lifelong sexual monogamy causes people needless suffering. Research supports the claim that lifelong sexual monogamy is unnatural and unrealistic. Biologists have strong evidence that social monogamy is rare among animals, and that sexual monogamy is even more rare, as most socially monogamous species are not sexually monogamous. The fact that 80-85% of societies allow polygynous marriage further argues against the idea that sexual monogamy is built in to human nature. Studies of extramarital affairs and divorce provide evidence that lifelong sexual monogamy is unrealistic. Substantial numbers of people engage in extramarital sex.  About half of married people in the United States divorce, and the majority of divorced people find new partners and marry again. Many people, perhaps the majority, simply do not live up to the expectation of lifelong sexual monogamy.