Almost 30 years after Annie Hall, the “New Yorkers with sexual hang-ups” movie is beginning to feel as old as the Iliad.

The apartments are too big for the couples’ income, the children conveniently appear and repeat something an adult wants kept quiet, and the characters are the kind of people who would be better off alone and bitter.

Welcome to Trust the Man, the latest installment in the “Not tonight, I have a headache” sex farce. Starring Julianne Moore, David Duchovny, Billy Crudup and Maggie Gyllenhaal, the movie benefits from the fact that all four actors have a collective chemistry, but not even they can escape the fact that everything about this movie has been done to death.

Moore and Duchovny play Tom and Rebecca, parents who have different ideas about how much sex is “too much.” They visit a therapist — because everyone in New York does, according to the movies — and Rebecca accuses Tom of being a nymphomaniac. “I just like it,” he says.

Crudup and Gyllenhaal play the more believable of the two couples, Tobey and Elaine, together for seven years but unmarried because — you guessed it — he is afraid of the commitment.

Scenes that unite the foursome are appropriately charming although the plot contrivances are as obvious as the restaurants are too expensive. Moore’s talents as a comedienne are underrated, and Duchovny plays a creep perhaps too well.

It is where writer, director and Moore’s husband Bart Freundlich takes the characters that is so mechanical. There is the old college flame that resurfaces and tempts Tobey, the hot single mom at daycare who ignites fantasies of infidelity for Tom and Rebecca’s overeager, younger male co-star in a stage play.

To his credit, Freundlich doesn’t take every subplot in Man the way they usually go, but the characters’ separate journeys would be tolerable if they weren’t there only as temporary roadblocks to a double happy ending. The movie’s central flaw is in failing to convince its audience the characters have even the slightest possibility of ending up apart. Neurotic and two-dimensional, they certainly deserve each other.

Trust the Man manages to be depressing and occasionally fun for the same reason: the cast. It’s disheartening to see great actors spouting such dreck, but with lesser talent, the movie would have been a train wreck from the credits.