The findings by the Marriage Foundation suggest “pre-nups” ‑ legal agreements that dictate how money and assets are divided should the marriage fail ‑ are not just for the rich and famous.
Many Hollywood stars have high-profile pre-nups, and last year it was reported that David and Victoria Beckham’s son Brooklyn signed an agreement with fiancée Nicola Peltz.
The foundation’s conclusions are based on a survey by Savanta ComRes, which asked more than 2,000 adults who were married or had been, whether they had the legal agreement in place, or knew someone who had.
It found their use was surprisingly common, with 20 percent of those married since 2000 answering “yes”, compared with just 1.5 percent who were married in the 1970s, five percent in the 80s and eight percent in the 90s.
Until the high-profile divorce case between German paper company heiress Katrin Radmacher and her French ex-husband Nicolas Granatino went to the UK Supreme Court in 2010, there was a great deal of legal doubt about the enforceability of pre-nups above and beyond the normal constraints of divorce law.
The survey also highlighted a concentration of top managers and senior executives who had used, or knew of, pre-nups.
More than four in 10 (44 percent) of those in the higher managerial, administrative or professional category said “yes” compared with 18 percent for the other four employment groups, including mid-level managers, skilled and semi-skilled workers.
Foundation research director Harry Benson said: “This survey, a world first, has delivered some truly surprising results ‑ chief among these is the much wider use of agreements than any prediction or claim. At the levels suggested by the data, they are no longer a legal curiosity or quirk associated with the mega-rich.
“They appear to be becoming an integral part of getting married for large numbers of couples, particularly for high earners and those with substantial assets.”
The survey found that pre-nups were most likely among couples where the wife earns the same or more than their partner, and less likely among couples where the wife is better educated.
In another counterintuitive finding, the survey suggested that a pre-nup is not associated with higher levels of divorce.
Mr Benson said: “Pre-nups don’t change the risk of divorce.”