Based on Jane Smiley's novella "The Age of Grief" (Craig Lucas wrote the screenplay), "Secret Lives" is a deft balancing act — a fantasy that's rooted in the everyday push-and-pull of marriage and family. Unlike the symphony conductor in Preston Sturges' classic screwball comedy "Unfaithfully Yours" — who conducts while fantasizing about ways to avenge his wife's infidelity — David finds himself constantly pulled out of his reveries. His bourgeois life keeps getting in the way.

The director, Alan Rudolph "(Afterglow, Choose Me"), builds to a 20-minute centerpiece that is one of the most deceptively brilliant sequences in recent movies. David — barely recovered from his own bout with the flu — must tend to Dana, and then each of their three daughters, as they successively fall ill. He glides through the house — his own feverish visions taking shape around him — trying to hold everything together.

The point, at once poignant and pathetic, seems to be that family life gives us no time to contemplate the messes we sometimes make of our lives. David's actions might mark him as a kind of domestic hero, the man who will rise to protect his family, even after he believes his wife has betrayed him. But his heroism — like a Camus or Beckett character — is more born out of necessity, and a certain lack of imagination; he can't think of doing anything else, so he will contentedly play the cuckold.

This kind of existential melodrama usually comes off cold and academic, but "Secret Lives" is suffused with empathy. Rudolph and Lucas satirize the paranoia that lurks at the heart of all romantic relationships, but they also understand that paranoia as human — as perhaps the only choice we have.

Rudolph directs in his trademark style: elusive and teasing, droll and slightly whimsical. But for once his work doesn't slip away into the ether, I think because he's found two unfussy, intensely focused lead actors who know how to ground abstract ideas in nuanced, recognizable feelings. With their fierce gazes and tortured silences, they take us right to the heart of tragedy — showing us how hate can build up alongside love, and allow a perfectly stable marriage to unravel in an instant.