Secret to marriage: Find a man five years older who's never been wed

The research, called Optimising The Marriage Market, appeared in the European Journal Of Operational Research, which usually analyses business decisions.

Academics including Dr Emmanuel Fragnière of the University of Bath studied interviews with 1,534 Swiss couples who were either married or in a serious relationship. Five years later they followed up 1,074 of the couples to see which had separated…

Couples where the wife is five or more years younger than the husband are the least likely to hit trouble, with their divorce rate six times less.

With education, couples in which neither partner has studied much are the most likely to break up. Those where both are well educated are half as likely to divorce.

If the woman is better educated than the man, they are eight times as likely to stay together than the uneducated couple, and three times more secure than if the husband were more of a bookworm than the wife.