Just as most of our literature is earnestly proclaiming that relations between the sexes are at an impasse and that marriage and the family are dying if not already dead, along comes Jean Gould's funny and touching first novel. "Divorcing Your Grandmother" insists, with a kind but bemused affection, that the labor of love, however absurd and uneasy it may sometimes be, should not be labeled lost.

A true comedy of manners for our time, the novel takes its title from its protagonist, Kate Cummings: Leaving her husband George would be as impossible, she says, as "divorcing your grandmother."

Kate, a mid-fortyish anatomy professor in suburban Boston, and George, a psychiatrist, have been married forever and have known each other even longer: Their common history includes burying a treasure trove of licorice in the back yard of Kate's house when they were in the fifth grade. In high school Kate briefly deserted George for the football hero because, she tells him years later, of the latter's "razzle-dazzle."

" 'I guess I'm not very exciting,' George said, hoping she'd contradict him. 'Maybe,' he continued with a grin, 'I could be one or the other.'

"She looked puzzled.

" 'Razzle or dazzle,' he said."

Perhaps because he is neither, Kate loves George's steadiness and predictability -- the pennies in his loafers are always shining -- and he loves her for the opposite. When they were once asked at a party to describe their favorite animals as a way of describing their mates, Kate had chosen a dog and George an eagle, as elusive as Kate: "Once she told him she had married him because he let her breathe. Loving was easy, she said. It was breathing that was hard."

But this is, after all, the '80s, a time when the day's Boston Globe reports that summer courses at the Cambridge Center for Adult Education ". . . were oversubscribed on the first day of registration. New sections of the following were opened: The Single Life, Life Begins at Thirty, Life Begins at Forty, Life With Children, Life Without Children, Is There Life After Fifty?"

It isn't, however, just this new age that confuses Kate and spurs her midlife crisis: She has ovarian cancer, and though a hysterectomy seems to be successful, she is face-to-face with mortality. No wonder, though she really does love George, she falls in love with Charlie, a thirtyish commodities broker who dazzles her with his card tricks, inventive sex and a plastic duck that "boogies across her tray table," and who loves Kate and his maroon Mercedes in equal measure. This is slightly more than he thinks he loves his wife Janet, who longs to return to a job as a social worker and who disapproves of the trappings of Charlie's success, especially his car.

Things begin to fall apart after George and Charlie meet in Kate's hospital room, but in ways more complicated than even she had feared. Janet, unbeknownst to Charlie, is George's patient, and George has known about Kate and Charlie all along, though not from Janet. It seems he's hired a detective, one Marabel Greenleaf of the Star Detective Agency. Soon Janet leaves the three children with Charlie and moves to an apartment in Cambridge, forcing him to become, as his mother addresses him in her nightly phone call, "Mr. Dustin Hoffman Kramer versus Kramer." George, the conventional psychiatrist, takes to wearing tennis whites to the office and then to treating his patients courtside. And this is just the beginning, as George devises an apt punishment for Charlie, and Ellen, the Cummings' daughter, returns from Maine.

Such is the stuff of situation comedies, of course, and Gould does indeed have an ear for deft one-liners. (Bemoaning the rigors of the family dinner hour, Janet says to Charlie, "Norman Rockwell lied.") But as any great comedic writer since Shakespeare has known, true comedy occurs when the ordinary is shown to be extraordinary and vice versa, and when the characters are not stereotypes but real people -- strong and weak, foolish and wise -- through whom we are both able to laugh at ourselves and to feel a renewed sense of order and hope. Unlike many of her contemporaries who work with similar material, Gould is never detached from her characters. Her eye is not satiric but loving, and because she cares about these people, so do we.

This is a wonderful novel about the way we live now -- which is, in love's requirements, pretty much the way we've always lived, at least since Elizabeth Bennet got her Mr. Darcy. In fact, if Jane Austen were alive today, her name could be Jean Gould.