A serio-comic take on a disintegrating marriage that just might not fall apart, Azazel Jacobs’ “The Lovers” is a relationship tale with jagged edges. Though a bit too cleverly contrived in the end, its voice is sufficiently distinctive to set it apart from other stories of modern marital discord.

The film is also blessed with two exceptional leads, Debra Winger and Tracy Letts. They play Mary and Michael, a couple whose life together has become pretty much limited to sleeping in the same bed and occasionally eating dinner together or sharing a bottle of wine. Both are having affairs—hers is with a writer named Robert (Aidan Gillen) and his with a dancer named Lucy (Melora Walters), but both decline to break things off completely with their mates until after an upcoming visit by their estranged college-age son Joel (Tyler Ross), who’s bringing along his girlfriend Erin (Jessica Sula). Neither Robert nor Lucy is at all happy about the delay in a commitment to them.

Complicating things is the fact that Michael and Mary, who have been sleepwalking through the exterior of their marriage for years, wake up one morning with a renewed passion for one another. They resume their love life, but furtively, in effect being unfaithful to their respective lovers. And when Joel—who’s been disgusted by the hypocrisy of their sham marriage—comes home to find them apparently besotted with each other again, it infuriates him all the more. The question, of course, is how they’ll handle their rediscovered common lust.

That’s all the story there is; the attraction of “The Lovers” lies not in the plot, which is awfully slender, but the details—the unexpected turns in Jacobs’ writing but especially the notes that Winger and Letts bring to their characters. Neither overdoes things—Winger, in fact, is more subdued than she has often been, and Letts exudes some of the comic befuddlement of the late character actor Edward Andrews, whom he rather resembles—but they invest Mary and Michael with the puzzled air that would naturally come upon partners who are surprised by the sudden reawakening of their desire for one another even as they plan to separate.

They bring a similar quality of quiet panic to their scenes with their respective lovers. Gillen’s Robert is a smooth operator whose attempts at manipulation Mary seems almost unable to resist, while Walters makes Lucy a frantic obsessive, certain that Michael will ultimately drop her for his wife. The difference between the two is exhibited in one of the script’s clumsiest twists—the idea that both would confront their rivals at roughly the same moment. While that turn can’t escape a feeling of hopeless contrivance on Jacobs’ part, the dissimilar approaches they take—Robert’s silkily abrupt, Lucy’s beyond histrionic—are entirely characteristic.

Lucy’s intrusion also plays a major part in the final reaction of Joel to his parents’ peculiar situation. As with Mary and Michael’s complicated emotions, it’s not easy to parse out exactly what’s driving the young man as he takes a stand, but that’s okay, because everything doesn’t have to resolve smoothly. That’s certainly true of Jacobs’ final twist, which some may dismiss as too clever by half but comes across as cynically fitting, given what has led up to it.

On the technical side the movie is fine, if unexceptional—Tobias Datum’s camerawork is more functional than elegant, but it will serve, as will Darrin Navarro’s editing. A more notable contribution comes from composer Mandy Hoffman, whose lush score bears at some points an uncanny resemblance to Pino Donaggio’s work.

There’ a calculated air to “The Lovers” that makes it seem not just an artful construction, but also a rather affected one. With Winger and Letts at the center, however, you’re likely to enjoy the artificiality rather than find it annoying.