We all know money doesn't equal happiness, but according to a new study, earnings do play a role in a happy relationship.
Research conducted by Patrick Ishizuka, a postdoctoral fellow at Cornell University's College of Human Ecology, found that partners who have similar salaries are more likely to stay together.
"Equality appears to promote stability," he explained in a paper published in Demography. "Equality in men's and women's economic contributions may hold these couples together."
Previous research suggests that equality in a relationship, especially when it comes to dividing household chores, promotes happiness and increases sexual satisfaction.
Additionally, when one person earns significantly more than their partner does, it can affect power dynamics in the relationship, causing dissatisfaction.
"The classic understanding of the power differential in couples is ... the person with more money in the relationship has the power," psychotherapist Marlin Potash told CNN. "The person who earns less can end up feeling their wishes and needs aren't as important and don't matter as much."
That's why Ishizuka noted in his paper that "equality might increase commitment or cooperation between partners since they're bringing similar economic resources to the relationship."
To make his conclusions, the author analyzed data from the U.S. Census Bureau's Survey of Income and Program Participation from 1996 to 2003. He also looked at data from the bureau's Current Population Survey, which includes 60,000 U.S. households.
Based on this research, Ishizuka also found that high-earning couples are more likely to tie the knot.
"Marriage is increasingly reserved for couples that have achieved a high economic standard," he explained.
According to Cornell Chronicle, Ishizuka's research confirms "the marriage bar" theory, which states that couples are more likely to wed when they reach a level of wealth that allows them to achieve the standard goals of married couples, such as buying a house.
"Once couples have reached a certain income and wealth threshold, they're more likely to marry. 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."
In Canada, the average age of newlyweds has increased. According to the 2011 census, the average age for a first marriage was 31 for men and 28 for women, compared to 28.5 for men and 25.9 for women in 1950.
Couples marrying at a later age could be a reflection of the fact that it takes longer to achieve an established career and income. Thus, people are more likely to wait and reach the marriage bar before tying the knot.
According to the 2016 census, more than a fifth of Canadian couples were living as common-law in 2016, up from 6.3 per cent in 1981. Nora Spinks of the Vanier Institute told the Toronto Star that the decline in marriage can be contributed to the fact that previous factors that made people get married in the past are less present today, such as religious beliefs, financial necessity, and a societal disapproval of sex outside of marriage.
U.S. psychologist and relationship expert Antonia Hall says changing attitudes about marriage also play a role.
"Many millennials were raised with rising divorce rates and broken homes, so they're far less likely to buy into marriage as the only or best form of relationship for themselves," Hall told Bustle. "Add to that the increase in educational costs and debt, and millennials feel less financially secure, which makes entering into what's considered a binding contract with their significant other far less appealing."
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