If you're planning to make your relationship eternal by getting married, then you should sit down for a moment and give the idea a second thought, suggests a new study.

Northwestern University study is based on the question: Will the partner who supports your hopes and aspirations while you are dating also help you fulfill important responsibilities and obligations that come with marriage?

The answer to that question could make a difference in how satisfied you are after tying the knot.

Believing a partner is there to help you grow into the person you aspire to be predicted higher relationship satisfaction for both dating and married couples, the study showed. But the belief that your partner helps you live up to your responsibilities and uphold your commitments only predicted higher relationship satisfaction after marriage.

For dating couples, the relationship itself tends to revolve around whether things are moving forward. Happiness with a partner depends on whether the relationship will grow into something more, whether a partner will support the dreams the other eventually hopes to achieve.

For married couples, the feeling that their partners are helping them to advance their relationships and realise their ideal achievements is still important. But the relationships of married couples, now more interconnected both practically and psychologically, tend to revolve around upholding the commitment made to their partners. Unlike dating couples, married couples also put a high premium on their partners' support of whatever they determine to be necessary obligations.

"In other words, the feelings of being loved and supported that people use to judge who makes a good girlfriend or boyfriend may not be completely trustworthy in deciding who makes a good husband or wife," said Daniel Molden, assistant professor of psychology at Northwestern and lead author of the study.

"Those feelings may only partially capture the emotions that will determine your satisfaction with the person you marry," the expert added.

The findings, Molden said, could be important in explaining why so many marriages fall apart.

The study, which will be published in the July issue of Psychological Science, included 92 heterosexual dating couples and 77 married couples.

They completed a battery of questionnaires that included an assessment of how much they thought their partner understood and supported both the hopes and responsibilities they had set for themselves. To measure how different types of perceived support were related to happiness with the relationship, couples also completed well-validated measures of satisfaction, intimacy and trust.

Illustration: Uttam Ghosh