As many as two million people could be moving in together for money, not love, as the cost of being single reaches £1,200 a year.
The benefits of sharing the cost of rent, food and energy leave cohabiting couples with more than £100 extra disposable income a month, research by First Direct found.
That means everything from saving to meeting mortgage payments is more of a strain without someone to share the burden with.
Even the cost of car insurance is higher for singles - data from confused.com found that a single female driver will pay more than twice as much on average as one who adds a spouse to their policy.
People without a live-in partner are also less able than couples to afford lifestyle luxuries, such as regular holidays, nights out, gym membership and a cleaner, according to First Direct’s findings.
And the savings available mean in the past year alone 1.9 million people have moved in with partners sooner than they wanted to simply to reap the financial benefits, housing charity Shelter calculates.
On the other hand, costs keep couples together that perhaps shouldn’t be - Shelter found nearly 10% of the people it asked had been forced to live with a partner because the cost of living apart was too high.
“Moving in with someone is a major life decision, and it’s shocking that so many people say they are rushing their relationships because they literally can’t afford to live without their other half. Everyone knows relationships are hard work, and being forced to take decisions you are not comfortable with only adds to the pressure,” said Shelter chief executive Campbell Robb.
“Just as concerning is the news that so many couples who have split up are unable to make the final break due to the cost of moving out and starting again. Anyone who has been through a relationship breakdown knows how painful it can be, and being forced to continue living together is extremely stressful for all concerned.”