In her series on monogamy, Tracy Clark-Flory had trouble finding a social scientist able to offer empirical evidence supporting the practice:
Eventually, I found a willing defender: Justin Garcia, an evolutionary biologist at Binghamton University. It's no accident that he's a scientific advisor to Match.com, which needs all the romantic optimism it can get. There's just one small technicality: His evidence supports social monogamy, which is not always, or even often, accompanied by sexual monogamy (more on that later).
From the interview:
Should we shift our focus to social, as opposed to sexual, monogamy?
The problem if we just embrace the social and not the sexual is that jealousy is also an evolved system. Humans in particular get very jealous, especially over infidelity. I just finished a study with a colleague of mine, we looked at men's and women's reactions to infidelity in over 100 different societies around the globe using ethnographies. It's almost always the case that when your partner sexually betrays you, people get upset and react intensely. There's one story of a woman chopping off her [straying] husband's testicles at a group event and throwing them in a fire pit. There are intense reactions that both men and women engage in.
I'm inclined to say that social monogamy is a biological prerogative because, particularly for males, it means that you know who the parents of your offspring are. But then there's also a psychological component: Having that deep relationship with someone can be really magical and people all over the world experience that, but we don't give enough serious attention to how powerful those bonds are. They can really change someone's life, often for the good.
The Dish 