Far fewer Washington area marriages are breaking up now compared with a decade ago, with some jurisdictions reporting a 30 to 45 percent drop in the divorce rate since 1980.

In the District and most of the suburbs, the divorce rate is now lower than the national average of 4.7 divorces for each 1,000 people.

The steepest decline in divorces occurred in the District, where the number of divorces fell from 4,700 in 1980 to 2,400 last year. With the city's population dipping only slightly over that time, the drop represents a 45 percent decline in the rate of divorce.

In the suburbs, divorce was one of the few things that did not accelerate during the expansion decade of the 1980s. As the populations of Montgomery and Fairfax counties soared, the number of divorces barely budged, dropping divorce rates significantly.

Montgomery County has so few marriage breakups now that its divorce rate is 32 percent lower than the national one.

Demographers, sociologists, ministers and marriage counselors offer several explanations as to why couples are not rushing to divorce court in the numbers they once were. Some say that people are delaying marriage until later in life, when the risk of divorce is reduced. Others attribute the decline to more couples living together without marrying; if they break up, they do so without a formal divorce. Still others say that couples are less casual about marriage and more hesitant about divorce.

"It's difficult to know what the decline means," said Johns Hopkins University sociologist Andrew J. Cherlin, who has specialized in demographic trends on marriage, divorce and family. "It could mean that people are less likely to divorce than a decade ago" or it could be a combination of several factors, he said.

Nonetheless, Larry L. Bumpass, president of the Population Association, says it may be too early for a "collective sigh of relief" over the slowdown in divorces.

Because the 10 percent decline in the national divorce rate since 1981 follows a meteoric rise over two decades, Bumpass said the risk of divorce is still very high.

Couples now heading to the altar still have a slightly better chance of separating than staying married, Bumpass said.

Washington area marriages, in particular, have a better chance of lasting because brides and grooms here are typically wealthier, better educated and older than couples nationally. Generally, according to national surveys and academic studies, money, education and maturity make love last longer.

The median income for Washington area households is more than $10,000 higher than the national median, according to the Census Bureau, which also heralds this area as having the highest concentration of college graduates in the country.

The age of brides and grooms has been steadily increasing. The typical American bride was 25 years old on her wedding day in 1987 and the typical groom was 26, according to the National Center for Health Statistics.

Virginia couples mirror the national profile; Maryland couples are generally one year older and District couples are the oldest, with the average bride 28 and bridegroom 29. The local and national averages both have risen about two years since 1980.

Oliver Nophlin waited even longer. The District resident was 34 when he married his wife, Deborah, a physician and professor at Howard University. "It helps if you're older. For one thing you realize that marriage means you don't walk out if you get mad," said Nophlin, now 42.

Older couples aren't as starry-eyed about marriage and have the experiences of surviving through tough times, said Nophlin, a massage therapist who works with athletic teams.

These days, he added, "people have more stick-to-it-iveness. When I was in Vietnam, nobody talked about staying with one person forever. Now people are more serious-minded; they're talking about the ozone layer, AIDS, the price of housing."

"The naive optimism of 'doing your own thing' is swinging back to 'This isn't easy and I don't want to do it alone,' " said Fairfax family therapist Eileen C. Selz, who has counseled more than 100 couples.

A keener awareness of the pain of divorce, perhaps because of breakups of parents or friends, and a reluctance to go through life alone appears to have sobered people about the effects of leaving their spouses, she said.

In a recent article in Demography, the journal of the Association of Professional Demographers, Bumpass also said that the concern about AIDS may have contributed to the decline in the divorce rate, but added that the downturn largely occurred before there was widespread concern about the sexually transmitted disease.

Between the dawn of the Kennedy era and beginning of Reagan's administration, the American divorce rate doubled, according to the National Center for Health Statistics. The peak divorce years were 1979 and 1981, when there were 5.2 divorces for each 1,000 people.

Mark B. Sandground, a widely known Washington divorce lawyer, remembers the peak years well. "Those were the heydays," he said, "when people got divorced because she wore a red blouse and he didn't like red."

Selz, who counsels couples at the Family Counseling Centers of Northern Virginia, says commitments are now taken far less casually. An increasing number of couples seek counseling, and seek it early, a sign, she said, that they are not willing to give up on marriage easily.

"I'm seeing people who have been married two months, six months, two years -- that's new," she said. "Just like health, marriage trouble is now perceived as something you don't wait until it gets really bad to have looked after."

The Rev. Michael J. Kelley, associate pastor of St. Augustine Catholic Church in the District, has noticed a large number of people who come to his Northwest Washington church planning to marry but then deciding against it.

Three of 10 couples that attend St. Augustine's required marriage preparation classes call off their wedding, he said. The preparatory discussions -- recently reemphasized by many congregations throughout the country in response to the high divorce rate -- force couples to discuss over as long as six months their values, expectations and plans for children.

"I really do think they're having an effect," he said. "That's great if they prevent three out of 10 mistakes."

Once they do go through with the wedding, Kelley said, there is growing determination to make it work. Last Sunday, the church celebrated the fifth anniversary of what is believed to be the nation's largest black Marriage Encounter program, a retreat for couples.

At the same time divorce was becoming less common in Washington, marriage was becoming more popular.

In the metropolitan area, the marriage rate rose during the 1980s, bucking the national trend. There were 9.6 marriages for every 1,000 Washington area residents in 1980 and 10.3 weddings for every 1,000 in 1986, the latest figure available.

While wedding consultants and jewelers aren't complaining about the recent trends of romance, some divorce lawyers are.

"I get 15 calls a day now instead of 25," said Sandground, the Washington lawyer, who said his colleagues had noticed the slowdown too.

But after more than three decades in the business, he added, he did not think for a minute fewer divorces meant couples are more satisfied or happier.

"Heck, no, I don't think it has anything to do with that. It's all about money," he said. "There is a high cost to leaving."

Staff researcher Bridget Roeber contributed to this report.

Rate per 1,000 population.....Number of divorces/......Population

United States.................annulments

1980 5.2......................1,189,000...............226,546,000

1989 4.7......................1,163,000...............248,239,000

District of Columbia

1980 7.3......................4,682.......................638,432

1989 4.0......................2,398.......................604,000

Anne Arundel County

1980 4.0......................1,470.......................370,775

1988 3.4......................1,407.......................417,600

Alexandria

1980 6.7....................... 683.......................103,217

1989 4.7....................... 525.......................110,300

Arlington County

1980 4.8....................... 739.......................152,599

1989 4.1....................... 691.......................167,000

Fairfax County

(including Falls Church and Fairfax City)

1980 4.4......................2,731.......................625,806

1989 3.5......................2,875.......................801,000

Howard County

1980 2.7....................... 320.......................118,572

1988 3.7....................... 599.......................163,000

Loudoun County

1980 4.3....................... 247....................... 57,427

1989 3.9....................... 351....................... 89,000

Montgomery County

1980 3.6.......................2,111......................579,053

1988 3.2.......................2,248......................704,900

Prince George's County

1980 4.0.......................2,688......................665,071

1988 3.4.......................2,392......................701,000

Prince William County

(including Manassas and Manassas Park)

1980 3.9........................ 649......................166,665

1989 3.9.......................1,043......................266,459

*Statistics refer to court-ordered annulments, not annulments issued by the Roman Catholic Church.

NOTE: 1988 and 1989 figures are estimates.

SOURCES: D.C. Vital Statistics,U.S. Census Bureau, local governments, Virginia Center for Health Statistics, Maryland Department of Health and Mental Hygiene