COMMITMENTS : Should You Stay Together for the Kids’ Sake? : Relationships: Couples may be continuing in less-than-happy marriages for their children. But that may not always be the best thing.

Francesca Johnson, the unhappy Italian war bride living in Iowa with a nice but lumpy husband and two children in “The Bridges of Madison County,” meets a gentle and loving traveling photographer. They have a four-day affair, but at the end Francesca stays in Iowa.

She tells the photographer that her leaving would devastate her husband.

And her children?

“They would never be able to live through the talk,” she says.

Big curtain. Big tears. And everywhere people say, “Isn’t that beautiful? People do stay together because of the kids.”

The treacly novel, which the movie followed but doesn’t slavishly adhere to, has been on the bestseller list for almost three years. A recent New York Times essay by Caryn James said the key to the popularity of “Bridges” is that it is “about renouncing grand passion in favor of being a wife and mother. . . . The message is reassuring to readers who have renounced their own great passions, and even more reassuring to those who have never found any.”

A February Time magazine cover--”Should This Marriage Be Saved”--explored the trend toward couples sticking it out, in most cases, because they have children.

Is this, then, a trend? If it is, is it a good one? Or is it more, in the words of a Connecticut man who is on his second marriage and has three children, that grown-ups are just plain tired?

“You’ve got to come to the decision about where you’re carrying your family,” said the man, who asked not to be identified. “To me, family comes first. You may not be on best terms with your spouse, but your kids are looking to you as role models. It’s not like you don’t consider your wife a good role model. It’s not like you hate your wife.”

But is it like you love her?

“Often I’ve heard kids say, ‘I wish they’d get divorced,’ ” said Constance Ahrons, USC professor of sociology and associate director of the school’s marriage and family therapy training program who wrote last year’s “The Good Divorce.” “The kids felt like they made it worse. Staying together for the sake of the kids and working on your marriage should be applauded. Staying together as an excuse cannot be good for the children.”

In 1993, 2.3 million couples got married. That same year, 1.2 million couples divorced. This year, the Bureau of the Census says that four of every 10 first-time marriages will end in divorce, compared to six of every 10 among people who have been married twice or more.

“Divorce rates are lowering, but they went through a dramatic peak,” said Cathleen Gray, Catholic University assistant professor of social work and a therapist in private practice in Washington. “We talk about them not lowering, but leveling off.”

Froma Walsh, director of the Center for Family Health at the University of Chicago, said other factors in the leveling-off are that people are waiting longer to marry and that married couples are--by and large--more open to marital counseling or therapy to strengthen their relationships.