SYDNEY – Living happily ever after needn't be only for fairy tales. Australian researchers have identified what it takes to keep a couple together, and it's a lot more than just being in love.

A couple's age, previous relationships and even whether they smoke or not are factors that influence whether their relationship is going to last, according to a study by researchers from the Australian National University.

The study, titled What's Love Got to Do With It, tracked nearly 2,500 couples – married or living together – from 2001 to 2007 to identify factors associated with those who remained together, compared with those who divorced or separated.

It found that couples in which the man is nine or more years older than his wife are twice as likely to get divorced, as are men who get married before they turn 25.

One-fifth of couples who have kids before marriage – together or from a previous relationship – separated, compared to 9 per cent of those with no children before marriage.

Women who want children much more than their partners are also more likely to get a divorce.

The study also showed about 16 per cent of people whose parents separated or divorced experienced their own marital separation, compared to 10 per cent for those whose parents stayed together.

Also, partners who are on their second or third marriage are 90 per cent more likely to separate than those in their first marriage.

Not surprisingly, money also plays a role, with up to 16 per cent of respondents who indicated they were poor, or cases where the husband was unemployed, saying they had separated, compared with only 9 per cent of couples with healthy finances. The wife's employment status was found to have no significant effect.

Couples where only one partner smokes are more likely to split up.

Factors found to not significantly affect separation risk included the number and age of children born to a married couple and the number of years couples had been employed.

The study was jointly written by Rebecca Kippen and Bruce Chapman from the Australian National University, and Peng Yu from the Department of Families, Housing, Community Services and Indigenous Affairs.