Love is a tricky business, with the answer to finding it and keeping it still desperately sought after.

However, the key to a happy relationship could lie in the amount of money you collectively earn.

Not only are couples that earn a higher amount more likely to get married, but people with similar salaries to their partners also have a greater chance of staying together with them, a study has claimed.

Patrick Ishizuka, a postdoctoral fellow at Cornell University’s Population Centre, has written a paper published in Demography that explores the way in which money can affect the state of a relationship.

One aspect of his research investigates a theory known as “the marriage bar”, which dictates that couples are more likely to tie the knot when they’ve achieved a certain level of wealth.

“Once couples have reached a certain income and wealth threshold, they’re more likely to marry,” Ishizuka said.

“They want to have a house and a car and enough savings to have a big wedding; and they also want to have stable jobs and a steady income.”

According to Ishizuka, couples with a weaker economic standing are more likely to separate, despite previous research suggesting that couples with less money place a lot of value on the notion of marriage.

“Marriage is increasingly reserved for couples that have achieved a high economic standard,” he stated.

“Rising divorce rates since the 1960s have also been steepest for individuals with less education.”

However, the amount of money that couples earn as a pairing isn’t the only important factor in determining the strength of their commitment to one another.

Couples who live together and earn similar salaries also have a stronger probability of staying together, Ishizuka claimed.

“Equality appears to promote stability,” he said.

“Equality in men’s and women’s economic contributions may hold these couples together.”

People in relationships who live together have a greater propensity towards egalitarian views than those who move from being single directly into married life, Ishizuka said.

Cohabiting and getting to know one another better in a domestic setting before getting married can influence the way in which people view traditional male and female roles.