Of course, there are unsanctioned alternatives. Adultery, anyone? Or perhaps serial monogamy – divorce after divorce after divorce (after divorce), Ron Perelman style. You could do polygamy, I suppose, although besides HBO, it's usually a moot point. And then there are open relationships.

"The New Monogamy," New York magazine dubbed it back in November. Being interested in any method that allows you to have your cake and eat it too, I was intrigued. The article detailed a trend (perhaps burgeoning, perhaps imagined) of extracurricular-dalliances-as-homeopathy, easing the strictures inherent in traditional staid, exclusive relationships.

The writers, seasoned relationship advisers Em & Lo, first outlined their own beliefs: Namely, that although monogamy isn't the natural state of affairs, it's what "happily-ever-after requires."

While we may yearn to philander, we attempt fidelity as a way of upholding the relationship golden rule. Then we fool around behind our partners' backs. Or think about fooling around behind our partners' backs – both of which seem easier than negotiating the complex minefield of our conflicting desires: We want to experiment, but we cannot handle the thought of our partners doing the same.

There are people, however, who believe there's another way, who view sex and relationships through an unconventional paradigm – who, when faced with a choice between black and white, rebel and pick pink.

Writer Jenny Block is one of them. She details her experiences in "Portrait of an Open Marriage," published in the April/May issue of Tango magazine.

Block, 36, is petite, with long, highlighted brown hair, huge brown eyes and a lithe dancer's body. The daughter of a rabbi, she lives in the South with her husband of nine years and their young child. She is, she says, just the "average woman next door."

The average woman next door with a unique spousal arrangement, that is. After years of traditional forsake-all-others marriage, she started feeling "itchy." She cherished her husband, but longed for what he couldn't give her – "Mystery. Sexual tension. Craving."

"Human beings are sexual animals," she explained to me over Equal-laden lattes last week, "but we don't actually live that way." Instead, she said, we separate our lives from what we desire – and how do we compensate? Affairs! Porn! Living vicariously through bed-hopping celebrities!

"It seems like we're working against biology," says Block.

She realized that she didn't have to fall in lock step with established cultural commandments – so she asked for permission to engage in outside liaisons. Talking it through with her reluctant husband, they came to a simple – although not simplistic – preliminary agreement: they would try it out and see how it felt.

The ensuing experience, Block writes, was "interesting and hard and wonderful and confusing." Negotiating that line – the one between sex and love and jealousy and possession – has taken creativity, compromise and a lot of communication. There have certainly been complications (like how much to tell and how much to leave out). And although her husband "intellectually" gets it, he admits, "sometimes, emotionally, it's hard."

Not to mention, Block says, "We have absolutely, positively no models for what we are doing."

They really don't. If Block isn't the first woman to write about her lifestyle without using a pseudonym, she's at least the vanguard of a very small group. Indeed, with her choices largely frowned upon by society, Block understandably worried that she was "crazy" for telling her story so openly (with photos, no less). "Would my neighbors still let my daughter play with their kids?" she wondered.

Still, she felt strongly that it was time for someone to start the discussion. An adamant champion of personal freedom, Block doesn't disparage those who stick with traditional exclusivity. "If an open relationship isn't for you, I'm not going to tell you to have one," she says. "But if you can find happiness in something so simple, go for it!"

After all, she says, "There's hunger and war and children being abused – why get upset over this? This is just sex!"

For Block and her husband, it certainly seems like the right answer; their relationship appears secure enough to withstand what might topple a less confidant union. Perhaps ironically, Block has found that being with other people "doesn't take away from the way I feel about my husband. It's exactly the opposite – I desire him more."

So what could destroy their marriage? "Being secretive, lying, or sneaking around … but the sex itself is not a threat."

In the end, having an open relationship has only reinforced her commitment to her husband. "I know for sure the grass isn't greener," she says with a smile.

And really, isn't that what we all want our partners to think?