Living happily ever after needn't only be 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 marriage is going to last, according to a study by researchers from the Australian National University.

The study, entitled "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 a husband who is nine or more years older than his wife is twice as likely to get divorced, as are husbands who get married before they turn 25.

Children also influence the longevity of a marriage or relationship, with one-fifth of couples who have kids before marriage - either from a previous relationship or in the same relationship - having separated compared to just nine percent of couples without children born before marriage.

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

A couple's parents also have a role to play in their own relationship, with the study showing some 16 percent of men and women whose parents ever separated or divorced experienced marital separation themselves compared to 10 percent for those whose parents did not separate.

Also, partners who are on their second or third marriage are 90 percent more likely to separate than spouses who are both in their first marriage.

Not surprisingly, money also plays a role, with up to 16 percent of respondents who indicated they were poor or where the husband - not the wife - was unemployed saying they had separated, compared with only nine percent of couples with healthy finances.

And couples where one partner smokes and the other doesn't, are also more likely to have a relationship that ends in failure.

Factors found to not significantly affect separation risk included the number and age of children born to a married couple, the wife's employment status and the number of years the couple had been employed.

(Agencies)