See? Joy was right. From the NYT:

New research at San Francisco State University reveals just how common open relationships are among gay men and lesbians in the Bay Area. The Gay Couples Study has followed 556 male couples for three years—about 50 percent of those surveyed have sex outside their relationships, with the knowledge and approval of their partners.

That consent is key. “With straight people, it’s called affairs or cheating,” said Colleen Hoff, the study’s principal investigator, “but with gay people it does not have such negative connotations.”

The study also found open gay couples just as happy in their relationships as pairs in sexually exclusive unions, Dr. Hoff said. A different study, published in 1985, concluded that open gay relationships actually lasted longer.

And as this study will inevitably become grist for the marriage equality debate: remember, kids, you don't have to be monogamous to be married or married to be monogamous. The Clintons? The Sptizers? The Vitters, Ensigns, and Craigs? Not so monogamous, as it turns out, but still married. And half all gay couples? Monogamous and not married. Straight people have been discussing open marriage—open straight marriage—for decades (swinging, "wife swapping," multiple partners), and never once has anyone suggested that an open straight marriage isn't a "real" marriage or that a heterosexual couple who isn't monogamous shouldn't be allowed to legally marry.

Marriage is only "defined" by monogamy—and procreation and kids and religion—when bigoted straight people want to deny gay people the right to wed. They reserve for themselves the right to be non-monogamous and married and childless and married and non-religious and married... all while denying the right to wed to monogamous gay couples that do have kids.