Dan Savage is the editorial director of The Stranger, a Seattle newsweekly, and the author of ''The Commitment: Love, Sex, Marriage and My Family.''

My favorite moment in Thursday night's G.O.P. debate: Newt Gingrich angrily denying his second ex-wife’s account of the end of their marriage — “Let me be quite clear: The story is false!” — and the socially conservative South Carolinians in the hall rewarding the former speaker of the House with sustained applause.

Marianne Gingrich's accusation shows that an honest open relationship is more scandalous than a dishonest adulterous relationship.

Let me be quite clear: Newt Gingrich wasn't denying that he had a six-year-long adulterous relationship with a Congressional staffer, a woman 20 years his junior, an affair that he conducted while overseeing the impeachment of Bill Clinton after his affair with a White House intern. Gingrich’s affair with a Congressional staffer is a long-acknowledged fact. That former Congressional staffer was sitting in the audience last night: her name is Callista, she’s the third Mrs. Gingrich, and she is — according to every profile written about her — a “devout Catholic.” (I was raised by devout Catholics. Devout Catholics are friends of mine. Devout Catholics do not have adulterous relationships with married men. Just sayin’.)

All Gingrich was denying with that “false!” was the allegation that he had asked his second ex-wife for an open marriage.

Newt Gingrich wants us to know that he did not ask his second ex-wife for an open marriage. An honest open relationship was never on the table. Newt and Callista’s six-year-long adulterous relationship was grounded in deceit and betrayal from the start, and Newt and Callista never wavered from the path of deceit and betrayal. Newt Gingrich was making an implicit promise to socially conservative voters: He did not ask his most recent ex-wife for an open marriage, and he will not ask any of his future ex-wives for an open marriage.

The lesson in Gingrich’s angry denial and the applause that greeted it: An honest open relationship is more scandalous, and more politically damaging, than a dishonest adulterous relationship. An honest, mutually consensual nonmonogamous marriage — which is not what Newt was proposing (you can’t negotiate an honest open marriage with your spouse six years into an affair) — is newer and somehow more threatening than the “traditional” cheating Gingrich engaged in.

It's difficult to put a figure on the exact number of couples who have honest open marriages. Very few couples who aren't monogamous are "out" about it. They appear to be monogamous, they work at maintaining that appearance, and they would rather have their families, friends, neighbors and co-workers believe something that isn't true than have to answer intrusive questions or deal with value judgments. They're what sex researchers call "socially monogamous."

Most of the people who've negotiated open marriage arrangements with their spouses realized, at some point in their lives (often after a failed marriage or two), that they simply weren't capable of being monogamous. Rather than continuing to make and violate monogamous commitments, they opted to level with themselves and their (sometimes new) spouses. Some of these couples are swingers; some are polyamorous; but most are what I like to call “monogamish": a relationship that's almost entirely monogamous.

Nonmonogamy — or monogamishamy — certainly isn’t for everyone. But it’s a better solution for those who are incapable of monogamous behavior, and a less socially harmful one, than an endless cycle of marriage, betrayal, divorce and remarriage. At Thursday night's debate, Gingrich told us that's he's the kind of person who thinks "grandiose thoughts." Imagine the grief that Gingrich could've spared himself and his ex-wives if he had given some thought, grandiose or not, to honest nonmonogamy.