time I'm really serious about someone, I guess. Monogamy isn't necessary for these things, but it would definitely make doing them less complicated. + Societal acceptance. Straight up, monogamy is the Western societal default. In some ways this makes monogamy hard to understand and communicate about -- because there are SO many assumptions and built-in expectations, and folks don't always agree on those expectations! A recent study found that 40% of young couples don't agree about whether or not they're monogamous. That amazes me, because I have never assumed that I was monogamous with a partner until we had a conversation establishing that we were monogamous... but I guess I can see how it happens, if people feel anxious about communicating and fall back on assumptions instead. Usually, however, being the societal default makes monogamy easier. Heterosexual monogamous people can get married with no problem, for example, and while marriage is obviously contested territory for non-hets, it's instructive that "gay marriage” is such a big political issue (while "polyamorous marriage" is currently nothing more than a specter right-wingers use to scare people about gay marriage). Outsiders usually assume that you're monogamous when you introduce your partner. Romantic comedies exalt monogamy; the media, and many people around us, associate monogamy with love. When you're monogamous, you never have to articulate your weird relationship structure to your parents. You rarely have to think outside the box about relationship problems, and you can go to any Western advice columnist or therapist and be sure that they'll recognize your relationship as legitimate. (Those of you who like privilege checklists might enjoy this monogamous privilege checklist, which is patterned after Peggy McIntosh's classic essay and white privilege checklist.) + Some people just like it better. Occasionally, people will toy with the idea of an "orientational" element to polyamory or monogamy: some