At one time or another, virtually every married person has dreamed, says marriage counselor Mel Krantzler, of trading in his or her spouse for a new model.

But the next time you are tempted to swap your Pinto-hearted partner for a Mercedes-like mate, he cautions, "pause a minute.

"The typical experience of divorced people who liberated themselves to pursue this dream is shock and disappointment. Almost half of those who remarry wind up in the divorce courts a second time within five years."

Instead of trashing a troubled marriage, Krantzler suggests revitalizing it by relating to your spouse in a "new and creative" way. "The probabilities of creating a happier life with your present partner are far greater than they would be with a new one."

This advice may surprise those familiar with the 61-year-old counselor's reputation as the "guru of divorce" -- earned through his best-sellers Creative Divorce and Learning To Love Again. (He wrote the first book after his marriage of 24 years ended in divorce and the second when he remarried four years later.)

But inspired by his eight-year marriage to psychologist Pat Biondi, co-director of Krantzler's California-based Creative Divorce, Love and Marriage Counseling Center -- he is now asserting: "The grass can be greener inside your relationship rather than outside it."

This is the message of his latest work, Creative Marriage (McGraw-Hill, 415 pages, $12.95). In the introduction, he deals with the apparent dichotomy between what he practiced and what he is preaching: "The fact of my divorce and what I learned from it, and the fact of my remarriage, really qualifies me to affirm the value of marriage. I have learned that divorce indeed can be a new opportunity for personal growth in certain circumstances.

"However, I have also learned that divorce need not be the answer for couples of good will who still have a little bit of the 'glue' of love left in their marriage; couples who realize that it takes two to create and perpetuate marital difficulties; couples who are motivated to change self-defeating behavior once they can identify what that behavior is; couples who value what they have, or had, but want something more out of their present relationship."

The key to reviving a failing marriage or keeping the spice in a good one, he says, is "establishing a climate where each partner regards and values the other as a separate and unique individual who is also part of an interdependent couple.

"This kind of creative marriage allows for mutual discovery of who each partner really is as a many-faceted person. It also creates the conditions for enabling each person to develop the widest range of his or her potentialities as a human being."

(Many remarriages fail, he says, because the partners don't adopt this creative approach. They view their new spouse the same way they viewed their old one -- as an extension of themselves. "So the spouse's face may have changed," he says, "but their problems remain the same.")

The '80s are "the perfect time," he says, for Creative Marriage to work. "Women and men are both changing to become more balanced human beings. There are more options for everyone. I see a trend in my practice for couples to create, not what their parents wanted from a marriage, but what they want."

But despite happy beginnings, he says, many couples fall apart as the marriage evolves "because they view change as a threat to the relationship rather than as a promise of its betterment.

"One woman told me her 4-year-old marriage was in jeopardy because she cut her long brown hair and dyed it blonde. She had wanted a newer, more fashionable look, but her husband claimed that, if she loved him, she wouldn't change from his image of the nice girl he married.

"People are often so intent on fixed images of who they are and who their spouses are, they are unable to view change as positive. But life consists of change . . . so to fear change is to fear life itself."

During the span of any marriage, says Krantzler, "change inevitably occurs in each of the spouses as well as in their relationship to each other." Just as Gail Sheehy isolated a series of distinct "passages" in the adult life cycle, Krantzler has defined a sequence of "predictable stages, experiences and challenges in every marriage."

The "six marriages within your marriage," he says, are:

* The "Now We Are a Couple" Marriage: A time of high hopes and great expectations mixed with anxiety, fears, shocks and surprises. Newlyweds consider pleasing their partner at all costs to be of paramount importance. This stage typically lasts three years.

* The "What's Happening to My Career" Marriage: Concern with status, income and achievement assumes the greatest importance. Tensions mount as both invest enormous physical and emotional effort in their careers. Each may begin to feel that their obligations to their spouse are holding them back from greater job success and happiness.

* The "Here We Are Parents" Marriage: Beginning at the point a couple decides to have a child, they must re-align the relationship to incorporate a new baby. No matter how well prepared, all new parents experience shocks and surprises when the infant arrives.

* The "Suddenly We're Older" Marriage: Beginning in the mid-30s and lasting through the late 40s, couples find the stability they may have yearned for--and discover it's a mixed blessing. Disenchantment with a spouse may be combined with panic over aging and boredom from the same old routines.

* The "Is the Past My Only Future?" Marriage: From about age 50 to 65, a couple's energies are primarily directed toward coming to terms with who they are now in contrast to who they were in the past. The struggle to deny the aging process gives way to recognition that each is indeed older. Depending on their attitude, couples may find this period a liberating or a depressing experience.

* The "Summing Up" Marriage: Inevitable separation by death looms on the horizon, forcing the couple to grapple with the question, "Was it all worthwhile?" The answer may depend largely on how well they have responded to the mutual development challenges in the five previous marital stages.

"A couple who anticipates, identifies and prepares themselves for each of these stages," says Krantzler, "can cope with them successfully."

And it's important to do so, he says, "because marriage appeals to one of the most fundamental needs humans have. We're basically bonding creatures, and our need for intimacy is as vital and necessary to us as eating and breathing."

As proof of this he notes: "The marriage rate is higher today than at the turn of the century. We've experimented with communal marriages, open marriages and other alternative arrangements and they didn't work."

But just because traditional values such as commitment, family and fidelity have again become fashionable, he stresses, "this doesn't mean a return to the marriage of the '50s.

"The present wide range of choices available to all of us--dual-career marriages, marrying later, marriage without children -- provide many of the building blocks for Creative Marriage. Marriage is now more a matter of personal choice than the price one must pay to affirm one's adulthood.

"Under these circumstances, those who marry have a greater sense of their personal worth. And that's a quality essential for making a Creative Marriage happen."