The old song says love and marriage go together like a horse and carriage, but it takes more than love to have a long and satisfying marriage.
Today is World Marriage Day, and experts exploring the foundations that lead to a lasting relationship say it helps if partners truly like each other and are committed to the union. It's also beneficial, they say, if a couple finds things to laugh about together and has similar attitudes and interests.
"The more similar you are to another person, the more likely you are to have a good relationship," says Robert H. Lauer, professor of human behavior at the U.S. International University in San Diego, co-author of two studies on long-term marriages and the book, " 'Til Death Do Us Part: How Couples Stay Together."
Similarities, he says, include values, beliefs, race, religion, amount of education, activities and personality type. "The more you share with the other person the more likely you are to have a satisfying and lasting relationship."
Admittedly, he says, certain kinds of differences might enrich a relationship, a premise he and his colleagues set out to examine. "But the result [of the research] was that the more you have in common, the better."
The desired degree of similarity is hard to pinpoint, say experts. "We tend to marry people like us," says psychologist Avshalom Caspi, assistant professor of psychology at the University of Wisconsin at Madison. "Just how similar is hard to know. [Our partners] are not exactly like us. They are familiar enough to make us comfortable but different enough that it's still arousing an interest."
Not only do people tend to marry people like themselves, say experts, but those who do tend to be happier. "We want some difference," says Dr. Caspi. "The difference is what we find somewhat arousing and interesting. The optimal is just enough difference."
Despite the psychological literature that suggests that like pairs thrive better than unlike spouses, some marriage counselors disagree.
"Research has not been able to prove that symmetrical relationships are better than complementary relationships," says marriage therapist Carol Werlinich, administrative director of the Family Service Center at the University of Maryland.
Between spouses who are more similar, she says, "you don't have to talk so much and share so much. You're thinking what he's thinking." With a spouse who is quite different, she says, "we must talk a lot; we don't automatically understand each other. We have to learn to negotiate our differences."
Flexibility and the ability and willingness to risk together rather than struggle alone, and to identify different ways to solve problems, are crucial.
Some psychologists who research personality say that when both partners are emotionally stable and the male does not engage in a lot of impulsive behavior such as gambling, drinking, drug use and philandering, the marriage is more stable and satisfying.
"If you want a low-conflict marriage, the best thing you can do is find a mate who is high on 'agreeableness' and high on 'emotional stability,' " says David M. Buss, assistant professor of psychology at the University of Michigan at Ann Arbor, who studied 107 couples in Washtenaw County, Mich.
How does Dr. Buss define agreeable? "Warm, lenient as opposed to critical, generous and not selfish." He defines emotionally stable as "secure; relaxed, not nervous; even-tempered; not envious or jealous compared to other people; and objective."
Another trait associated with stable marriage is "openness/intellect," which he defines as cultured, ( knowledgeable, intelligent, perceptive, creative, complex, analytical, broad-minded and literate.
But a satisfying marriage takes more than love.
"It just doesn't happen," says Janet Janyska, who has been married to her husband, Bill, for 25 years (see accompanying story). "It takes some work."