In her new novel, The Senator's Wife, Sue Miller employs a nifty device for comparing two marriages: A couple in their 30s—the soon-to-be-pregnant Meri and her husband, Nathan—move into one of two brick row houses; the adjoining house belongs to Tom, a former senator, and his regal wife, Delia, who've lived there for nearly 30 years. The four of them, especially the wives, strike up a friendship. This allows Miller to make the obvious comparisons—between marriages, young and old, as well as parenthoods, impending and past—but it also offers an interesting exploration of adultery.

Or, more to the point, a long, baggy marriage versus a short, tight one. (Tom and Delia have made room for affairs in their relationship, while Nathan and Meri have not.) Miller provides vivid portraits of both couples and then, by steering each toward surprisingly different outcomes, votes for the version of marriage she believes is likelier to offer enduring fulfillment. And yet the long shadow of judgment does not cast itself across the pages of this novel. The author seems to sympathize with all of her characters—both the philandering and the faithful—though she makes clear that their romantic choices dictate their larger fates.

It seems to me there is a certain amount of loneliness in marriage, even in the best of them. At times I feel as if I'm looking at my husband from the far end of a tunnel: I can't quite see him, but I know he's there. Be it from busyness or emotional withdrawal or exhaustion, marriage can expand to its roomiest brink before whooshing back in again to its once steadfast closeness. It is during one of these loose periods, when the pocket grows big enough to slide someone else into it, that I am guessing people fall prey to adultery. What Miller aptly illustrates in her novel is that this is not as precise a moral trespass as we'd like to believe. "'Well, isn't that what marriage is all about? Staying in it while getting out in some way too?'" Delia asks at one point, revealing the dilemma in her own.

So how does Miller vote? (Beware: spoiler ahead.) Tom and Delia, always somewhat estranged but able to keep up a fiery sexual alliance as a result, are given a complex, unhappy end, while Nathan and Meri, striving always to keep their romantic footing in commitment, are handed a cozy familial life. It would seem Miller, despite her appreciation for the complexities of marriage, does not think much of "arrangements."

To be honest, I'm not a fan either. Nothing gives me a worse headache than imagining some kind of '70s commune-y approach to marriage or, alternatively, soldiering on in a '50s trance after learning that your husband has been tickling someone else's fancy, so to speak. Or, for that matter, having to live the bifurcated life of someone who has secretly stepped out of, and back into, marriage. But here is where I part ways with Miller (or at least with her novel): I don't think that doom is the necessary outcome of an affair, just as I don't think a devout relationship guarantees fulfillment.

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