Jealousy and possessiveness usually get in the way of friendships between a person’s lovers. Yet this kind of friendship is one of the most natural varieties of all. Something of what one loves in one’s partner is usually found in the partner’s other partners, because of the power of sexual love as such. People linked in love tend to become alike, to coalesce. That’s why romantic comedy resonates so deeply with viewers, and why critics tend to worry about its well-being as a genre: its subject is not just companionship and life choices, it’s identity.

That’s also why the premise of the new romantic comedy “The Other Woman” is irresistible, and why its bland, thin realization is all the more disheartening. Cameron Diaz plays Carly Whitten, a New York corporate lawyer who is trailing a long string of unhappy relationships; she finds sudden love with Mark King (Nikolaj Coster-Waldau), a handsome and virile venture capitalist who neglects to inform her that he’s married. In planning an erotic surprise for him at his Connecticut home, she meets Mark’s wife, Kate (Leslie Mann), who, in turn, confronts her about the affair. From that confrontation, a friendship quickly develops (as Carly says, “We’ve been played by the same man”). When they suspect that there’s another other woman (Kate Upton) in the picture, they take off in pursuit and become amateur detectives, and ultimately learn even more about Mark’s hidden life.

As the movie veers from verbal wrangling to slapstick, much of what’s wrong with it can be pinned to the director, Nick Cassavetes, who has neither a sense of comic timing nor spacing. Much of what’s called “comic timing” is actually a matter of proximity or distance. Take a film by the director’s father, John Cassavetes—his last and least, “Big Trouble,” from 1986 (coming to Anthology Film Archives May 2-4), a comic version of “Double Indemnity” starring Alan Arkin as the insurance salesman and Peter Falk as the chump whose wife will do him in for the payout. The movie is no masterwork, but it has some uproarious moments, such as when the swinging Falk pushes the square Arkin to sample his rare stash of Norwegian sardine liqueur. Ingeniously, Cassavetes père polishes the raw comic gems of Falk’s great delivery and Arkin’s expressions in a thirty-second closeup; the timing works because the camera is in the right place.

In “The Other Woman,” Leslie Mann has an extraordinary showcase and she uses it flamboyantly, with an amazingly inventive range of inflections and line readings. She’s a major comic actor, but Nick Cassavetes does her no favors; his vague framings and ping-pong editing leach the immediacy from her performance. And he turns Diaz, playing a poised and serious person with a playful streak, into a caricature with a frozen smile and a flustery manner. The proof of the misdirection can be found in a scene that features Mann, Diaz, and Upton side by side: the eye is guided straight to the amateur, not because of youth or beauty but ingenuousness. Upton’s stolid expressions seem immune to the director’s overemphatic indications and keep a measure of spontaneity.

For a movie about love, “The Other Woman” is silent on what brings people together. The smooth talk and worldly wit that gets the affairs started and keeps them going remain unimagined. Mark’s relationships take place in a void—except for sex, which is the real subject of the movie. The opening montage shows Carly and Mark’s romance starting hot and heavy, and it’s a highlighted plot point that, in their eight weeks together, they had sex about fifty times. He’s got a furious sex drive and, apparently, he’s irresistibly alluring to women, who keep coming back for more.

The best thing in the movie (besides Mann’s very presence) is the mechanics of Mark’s deception, the machinations of the double and triple life. He has been manufacturing an endless repertoire of meetings and business trips and boys’ nights out in order to keep his affairs going. Whether he’s a sex addict in the clinical sense is unaddressed; what’s clear is that his lust is inseparable from his lies, the fulfillment of his desires inextricable from his callousness. He is, in every sense, a total dick, and the movie runs on the unasked question of whether a total dick is a better lover, whether Mark’s swaggering egotism is an essential part of (or maybe an inevitable result of) his sexual prowess—whether the cavalier heartbreaker with the massive technique isn’t a natural object of desire, and whether the good guy with whom one settles down confidently doesn’t also entail other kinds of settling.

In any case, though the action of the film shifts, early on, away from Mark’s deceptive machinations and toward Carly’s solidarity with Kate, he remains the axis of the story, the maypole around which the entire comic drama is organized. The point of the story is to tear Mark down, to demolish the phallic fetish and clear the ground for something more sheltering. (Note that Kate’s brother, the movie’s Mr. Nice Guy, played by Taylor Kinney, is a construction contractor.)

Yet Kate and Carly—and, for that matter, the “other other” and a host of others—are marked by Mark. He leaves his imprint on them, but “The Other Woman” doesn’t trace it, or, for that matter, reckon with his absence. He comes, and he goes. The movie has no unconscious, no quiet moments of reflection, no frustrated desires, no introspection, no real secrets. The story’s underlying symbolic power remains untapped. But maybe that very power suggests why romantic comedy is the genre most prone to distortions and deceptions, why it’s the one that offers the greatest temptation to sugarcoat and cut corners: because it’s all about identity, the stories it tells are the ones that people tell themselves about themselves. Its revelations are the most troubling, and its clichés are the most comforting.

Photograph: Twentieth Century Fox