After decades of claims they were 'living in sin' unwed couples might finally have the last laugh, with a new study finding unmarried partners are happier than their married counterparts.
The research — published in the Journal of Marriage and Family found that cohabiting couples experience greater levels of happiness and self-esteem than married couples.
Study leader Dr Kelly Musick from Cornell University looked at 2,737 single men and women, 896 of whom married or moved in with a partner over the course of six years.
The participants were questioned about their happiness, levels of depression, health and social activity.
The results showed a dramatic increase in general wellbeing immediately following both marriage and moving in with a partner.
This honeymoon period was short-lived however, with both married and de facto couples quickly reporting higher levels of depression and lower levels of happiness — though they were still better off than single people.
In the long-term, the study found that while married couples tended to have better physical health, cohabiting partners were generally happier and had higher self-esteem.
"We found that differences between marriage and cohabitation tend to be small and dissipate after a honeymoon period," Dr Musick said.
"Also while married couples experienced health gains — likely linked to the formal benefits of marriage such as shared healthcare plans — cohabiting couples experienced greater gains in happiness and self-esteem.
"Marriage has long been an important social institution… However our research shows that marriage is by no means unique in promoting well-being and that other forms of romantic relationships can provide many of the same benefits."