It's been the punchline of many a best man's speech over the years but now it's official.
Experts say it is better to be single than be involved in a poor-quality relationship.
A study found that being trapped in an unhappy partnership is so damaging to a person's health, they would be better off alone.
What's more, it gets worse the longer you are together, the researchers concluded.
Happily, they found that the reverse is also true – that being in a high-quality relationship benefits your physical and mental health.
The research team from the University of Buffalo in New York studied the relationships of young people from rural Iowa.
The subjects were from two-parent, married families, but the majority were not married.
With growing numbers of people now choosing to put off marriage in favour of more casual relationships, the scientists wanted to look at the impact this had on their health.
They asked the participants about the quality of their relationships, questioning how committed they were, how they dealt with criticism, and the support and affection they gave and received.
The team also asked how the partners behaved outside of the relationship – including whether they engage in risky behaviour.
Ashley Barr, assistant professor in the university's department of sociology, said the research showed that the longer people are in high-quality relationships – or, alternatively, the faster they got out of low-quality partnerships – the better their health.
'Health benefits begin to accrue relatively quickly with high-quality relationships and supportive contexts,' she said.
'And then we see detrimental effects from low-quality relationships - particularly, those low-quality relationships that last a long time.'
Professor Barr added: 'The findings suggest that it's better for health to be single than to be in a low-quality relationship.
'It's not being in a relationship that matters; it's being in a long-term, high-quality relationship that's beneficial.
'Low-quality relationships are detrimental to health. The findings suggest that it's better for health to be single than to be in a low-quality relationship.'
Dr Barr said relationships tended to change the older people became.
'It's rare today for young adults to enter a romantic relationship and stay in that relationship without ever changing partners or relationship characteristics.
'We now have two studies that found similar patterns and similar implications for those changes.'
The study was published in the Journal of Family Psychology.
Good news for singletons! It's better for your health to be alone than trapped in an unhappy relationship
Study looked at young people from two-parent families in America
Found poor relationships negatively affected physical and mental health
Scientists say quality of a relationship is what is important not act itself
By KATE PICKLES FOR MAILONLINE
PUBLISHED: 06:29 EST, 27 June 2016 | UPDATED: 07:26 EST, 27 June 2016