Think having a child will stabilize your shaky marriage? Think the "empty-nest" syndrome means couples are unhappy once their children leave home? Think a major illness is hard on an elderly couple's marriage? Think again.

A major long-term study debunks some commonly held myths about marriage, but upholds other beliefs. John N. Edwards, professor of sociology at Virginia Tech, joined Alan Booth of Penn State and David R. Johnson of the University of Nebraska, to do the nationwide study of men and women of all socio-economic groups, races, ages, and years married (some had been married since the '40s and '50s).

In 1980, the three interviewed 1,400 women and 633 men aged 55 or younger. They followed these same people through various stages of marriage, divorce, and remarriage, interviewing them again in 1983, 1988, and 1992, when some of the older participants were near retirement age.

The survey asks the participants such questions as how they think about their marriages and what they want.

In 1980, 20 percent of those interviewed had given some thought to divorce. That proved to be a predictor of divorce: people who scored high on thoughts of divorce were nine times more likely to get a divorce than were the other respondents.

Over the years, Edwards and his colleagues have found many predictors of high instability in a marriage. The age at which the couple married is one. The younger, the more likely to divorce. "It seems one reason for instability of people who married in their teens has to do with lack of preparation and unrealistic expectations of what they were going to get out of the relationship," Edwards said.

On the other hand, those who waited until after 30 to marry for the first time also had a higher instability rate than those who married in their 20s. "It appears they have gotten set in their ways and have adjustment problems," Edwards said.

Income was a predictor. The lower the income, the more thoughts of divorce, at least in the early years of the marriage. The longer the people had been married, the less low income seemed to prompt thoughts of divorce.

Health also was an issue. "We thought ill health might contribute to the destabilization of marriage," Edwards said. "And it's true of those who were younger (under 35) and people who had only been married five years or less. But at the other end of the life course, ill health seemed to have a positive effect. It contributed to the relative satisfaction people had with their marriages. Maybe it's the satisfaction of taking care of someone you love."

The couple's participation in the community -- church, clubs, neighbors -- also served as a predictor. Those who were integrated into their communities, especially if they'd been married a short time -- were more likely to have stable relationships.

Children, especially preschoolers, have a destabilizing effect on the marriage. Children can mean even more inequitable workloads for women -- already dissatisfied at having to do roughly 80 percent of the household chores, lowered rates of interaction between the husband and wife, and increasing dissatisfaction with the financial picture. "Children cost a lot of money and create a financial strain that has an effect on people's happiness with their marriage," Edwards says.

So people who tell partners in a shaky marriage to have a child to stabilize the marriage are wrong. The couple would do better to buy a house. Joint assets, not children, tend to solidify a marriage.

Once the children were grown and had left home, the marriage became happier, more stable, and more satisfying.

For those with extremely unstable marriages, two things influence their decision to divorce or stay married. First is their view of alternatives. If they think they can live alone or find a better spouse, if the woman has a job and knows she can support herself, they are more likely to divorce. On the other hand, there are barriers to divorce even when people see alternatives. Barriers include religious attitudes against divorce, families' opposition to divorce, a belief that divorce affects children adversely, and the presence of several joint assets.

The researchers continued to track people after divorce, many into remarriage and subsequent second divorces. "It's difficult to start over," Edwards says. The chances of divorce increase with the number of marriages.

A factor in a successful marriage or remarriage is the extent to which the spouse feels close to the other's family. The more integration, the less likelihood of divorce.

Also, there's the matter of the dwindling remarriage market and the reduced likelihood of finding a mate with similar religious, ethnic, or educational background, and of similar age. The more the discrepancy, the more chance of divorce.

Probably the most important factor in the stability or lack of it in remarriages is the presence of children from previous marriages. Stepchildren are destablizing, especially when both partners have children.

— Written by Sally Harris