Researchers suggest that the long-term health of a marriage is rooted in a couple's level of love and commitment as they say their "I do's."

A successful marriage is one that has maintained a high level of affection right from the start, where both partners behave as lovers and stay that way.

The investigators found that couples who were happily together 13 years into their marriage had been deeply in love and in tune with each other from the very beginning.

In contrast, those who were unhappily married reported having a more negative and/or ambivalent relationship toward each other when interviewed as newlyweds.

The investigators also point out that, whether good or bad, the general tone of relationships did not change over time -- with the exception that those who ultimately had a happy marriage began to see their partner as having a less contrary nature than they did when first were first married, whereas spouses in the other categories did not change their views of their partner's contrariness.

Couples who experienced friction at the very outset of a marriage headed for the exits at a much quicker pace. The authors theorize that these couples entered into marriage hoping that the simple act of "tying the knot" would turn discord into bliss -- only to leave the relationship when this proved futile.

The researchers conclude that partners who maintain long, happy marriages carry between them a deep love, affection and attachment -- feelings that first began during courtship.

Most people think that it's unresolved differences that undermine marriages, but it's not that at all. It's the loss of the bliss and the loss of the romance that's important, rather than increasing problems or increasing conflicts.

Couples headed for the rockiest road are those who had either an extremely long or extremely short courtship prior to marriage.

Either they don't know each other very well -- they fell in love too quickly and they have an unrealistic belief that the romance will continue in the same way over time. Or it's a long road to marriage, not because they are learning so much about each other, but because they have real problems in the relationship that they're trying to put aside in order to marry. When they discover that marriage doesn't have any magical properties they often quickly exit the relationship.

Current Directions in Psychological Science August, 2001;10