Intimate Partners: Patterns in Love and Marriage, by Maggie Scarf. New York: Random House. 428 pp. $18.95. EVEN as the merchants of romance - jewelers, florists, and greeting card manufacturers - are selling love in the Valentine's Day guise of anything sparkling, fragrant, heart-shaped, or red, booksellers are stocking their shelves with ``Intimate Partners: Patterns in Love and Marriage,'' one of the most sobering appraisals of marital relationships since Ingmar Bergman's ``Scenes from a Marriage.'' For 400 pages, author Maggie Scarf throws buckets of cold realism on the flames of romantic idealism. A diamond may be forever, but love, alas, is not, if her study is to be believed. The conclusion is hardly original in these days when even Ann Landers has become a skeptic. But some of the carefully reasoned explanations are new.
Why do people choose the mates they do, and what makes marriages last or fall apart? For Ms. Scarf, the answers to those questions lie more in the past than in the present. She makes a strong connection between ``the structure of early childhood experiences and later marriage choices,'' explaining how earlier relationships with parents and grandparents can exert a powerful influence on marital relationships.
Calling marriage ``the nearest adult equivalent to the original child-parent relationship,'' Scarf adds that ``what is so frequently sought in a mate - and then fought out with that mate - is some unresolved dilemma about a parent.''
It is a sobering, almost fatalistic approach, a classic case of the sins of the fathers being visited upon the children of successive generations. It is also an approach strengthened by the author's use of ``genograms,'' which she describes as ``emotional family trees'' charting each partner's attachments to parents, grandparents, siblings, and children.
Drawing on in-depth interviews with 32 couples - five of whom she uses as lengthy case histories - Scarf outlines the predictable stages of marriage: idealization, disenchantment, child-rearing and career-building, child-launching, and finally the rediscovery of each other during mature years.
In between, of course, are unpredictable stages, such as infidelity. Current research on extramarital sex, she notes, suggests that 50 to 65 percent of husbands and 45 to 55 percent of wives become extramaritally involved by age 40. As many as 2 out of 3 marriages may be affected.
Despite the increasing ordinariness of this disaster, the effects of adultery remain devastating. One partner's discovery of the other's betrayal, Scarf writes, marks ``the death of that marriage's innocence, the death of trust, the death of a naive understanding of what the relationship itself is all about.'' Yet she is quick to point out that an extramarital affair is only a symptom of ``a global marital disturbance; it is not the disturbance itself.''
How to resolve these disturbances? To help couples break old patterns of communicating and fighting, Scarf offers assorted behavioral tasks and sexual exercises, designed to forestall the unheeding horror of set monologues and reflexive responses.
Scarf avoids pointing an accusing finger at either partner in a troubled relationship, preferring to view them as ``couples in collusion.''
``In marriage,'' she writes, ``despite all overt evidence to the contrary, there really are no victims and villains; there is a deal that's been made.... Each one sees, in the partner, what cannot be perceived in the self - and struggles, ceaselessly, to change it.'' Later she adds: ``One partner cannot possibly assume the major portion of the relationship's power, burdens, and responsibilities unless the other partner has allowed (or even urged) that situation to develop.''
Scarf is at her best when she offers her own considerable insights on marriage. Ultimately, though, her own thesis sometimes sags under the weight of too much reportorial testimony. A little bit of ``he said/she said/I said'' can go a long way, and Scarf occasionally goes too far. Her tape recorder rolls endlessly on couples' conversations, stopping only long enough for her to interject unnecessary comments and descriptions.
She is, for instance, a tireless observer of women's cheeks (``her cheeks were marbleized with streaks of pink''; ``her cheeks were bright pink under the light brown coating of her tan''; ``there were streaky patches of mottled red on her cheeks''). It's not always easy to keep the five couples and their problems straight, or to care about them in ways that Scarf obviously hopes a reader will. Details become tedious, and the book repetitive.
With this volume, Scarf joins a growing list of authors who are expanding the genre of ``relationship'' books. ``Women Who Love Too Much'' became the No. 1 paperback best seller in several categories in 1986, and ``Smart Women/Foolish Choices'' spent weeks on the hard-cover best seller list. The latter, described by the publisher as a book that ``helps women understand themselves,'' will be followed in June by the same authors' ``Women Men Love, Women Men Leave,'' a book that supposedly ``helps women understand men better.'' The possibilities are almost as endless as the queues of lovelorn book-buyers who have created a thriving market for self-help books on the subject.
Scarf cites the line by the poet Stanley Kunitz, ``In every house of marriage there's room for an interpreter.'' At the rate we're going, there may be more interpreters than marriages. Scarf works at a level far higher than most of the crowd does, but the limits of the genre are becoming more apparent with each book. In the end, like most of her colleagues, she sometimes relies too much on exercises and strategies - techniques.
Amid the prose - all the data, all the talk, talk, talk - is something poetical, something (dare one say it?) holy being left out? Valentine's Day sentimentalists may ignore everything except the heart. But the opposite risk is that today's pseudoscientists of love will become so noisy with their analysis that not even Romeo and Juliet could hear their hearts beat.