BOOK REVIEW : The Messages in Marriages That Unravel : THE RAGGED WAY PEOPLE FALL OUT OF LOVE, <i> by Elizabeth Cox</i> , North Point Press, $18.95, 198 pages

“The permanence of the marriage was more real than the permanence of this leaving.” So it frequently seems to Molly after William tells her one day that he doesn’t love her any more. It is the slash of amputation, but, like a beheaded chicken, the organism continues to stagger and flinch.

Elizabeth Cox has chosen a title--”The Ragged Way People Fall Out of Love”--that says almost too much about her novel, almost preempting it. Preempting is her weakness; it is the downside to the exquisite detail with which she assembles her portrait of how hesitantly and unevenly two lives, joined for 17 or 18 years, unravel from each other.

Her book has a few happenings in it, but in the main, it records the advances and retreats of a process that is illness and recuperation at the same time. Cox writes warmly and tellingly about emotions but she can be overly perfect with them. The reader can feel like an ingredient in a recipe that is too rich. What she is best at is numbness: that which follows shock and precedes response.

William, an architect, and Molly, a painter with a growing local reputation, live in a pretty house in a pretty town in the hills of North Carolina. They have three children: Joe, an active and eager high school senior; Franci, an introspective and gnomic 13-year-old, and Lucas, age 7, cherubic and loving.

They are all quite lovely--more rich ingredients--and so is the marriage, except that it has lost its spark. William has a secret girlfriend we never see, and Molly is attracted to Ben, an astronomy professor. We do see Ben--before the book ends, he and Molly will become lovers--but he has only generic qualities: kindness, ranginess, intelligence and humor. He is a suitor acquired off the rack.

None of the characters, in fact, is much more than generic. Cox is less interested in showing us who they are--when Ben comes to a picnic he brings a bottle of Molly’s “favorite wine,” but we don’t even know if it’s red or white--than in how they feel. This is a book about parting; its people exist to undergo parting and recover from it. They are emotionally specialized.

The specialization can be superb. There is the shock that starts the book off. William makes his “I don’t love you” announcement and smiles. “She wanted to ask him why he smiled. She knew he didn’t mean to.”

It is a reflexive tic, like the decapitated chicken’s. Molly has her own; she shuts the window through which the voices of their children are heard, as if to isolate the matter of her world from this sudden bubble of anti-matter.

She asks, “Why?” But her real question is whether this is the first time he has felt this way. “Because she had felt that way many times though she never felt the necessity to say it.” Men, Cox is telling us. Women. Their distances.

Several months go by. William doesn’t leave. Nothing is decided. Their lives go on. She visits her widowed father, returns. They move about with extra politeness. She feels stiff and sore. He hangs about on Saturday afternoons, although they are a vacuum. He hugs the vacuum; he is afraid of losing it. It is the phony war.

One day William comes home; Molly is making noodles. He scoops up a few and goes upstairs. She knows he is leaving. So do we. Here, Cox paints with a chilling and diminished palette. When William comes down with a suitcase, Molly asks if he’d like to take some noodles along. The marriage’s reflexes have not stopped.

The story ambles on, with a side bit or two. Molly meets Zack, a troubled young man who was a victim of childhood violence, and finds a home for him with some nurturing friends. It could be a new start, but the past drags him back and he kills himself. The episode is awkward and lifeless. It seems dragged in so that at the end, Molly will be able to tell her children that the important thing is not what you lose, but what you can begin fresh.

Other incidents--Molly’s talks with her father, who tells of his own marriage problems and how he reconciled himself to them, and Joe’s loss of his virginity--also seem pulled in to serve one or another of the author’s purposes. More central is Joe’s apparent death in a car crash that kills two of his friends.

The incident is awkward, but it provides an occasion of apparent tragedy to show us which links remain and which have been severed between Molly and William. Again, the author makes superb use of the couple’s numbed reflexes to measure their distance and closeness.

When a policeman comes to report Joe’s apparent death, all Molly can think of is that William isn’t there. She tries to call him and can’t remember his number. When he arrives to share the ordeal, she offers to let him spend the night. But separation--so new and fragile--is all he has to hold onto; he refuses. Yet two weeks later, he telephones in the middle of the night to say that he can’t walk. Stress has paralyzed his legs. Molly goes over and they make love.

And this, loving as it is, marks a new stage. It is an odd but convincing confirmation that they have healed into their separate new lives. Again, Cox makes the point with subtle force. She goes on to smudge it by overemphasis, in a final scene where Molly, the children and Ben share Halloween dinner. They are dressed variously as skeletons, robots, a pirate, a Gypsy and so on.

“The Gypsy passes the potatoes to the two skeletons and the robots offered a roll to the Elizabethan queen,” Cox writes a little too quaintly. Molly announces that the final divorce papers have come through, and Franci explains to the others, in a Tiny Tim-like benison, that this means “that it’s not over yet.” Life, that is, and love.

Next: Judith Freeman reviews “Rima in the Weeds” by Deirdre McNamer (Harper Collins).