The “seven-year itch”, made famous by the 1955 film of the same name, is a phenomenon based on the assumption that marital dissatisfaction kicks in after seven years – and the temptation to be unfaithful becomes irresistible.

According to new statistics, however, Britons are sticking it out for a few years longer. Figures show that a marriage that ends in divorce has on average lasted 11.7 years.

This is a third longer than in 1985, when couples typically divorced after eight years and 47 weeks, suggesting the relationship probably hit the rocks after seven years.

Meanwhile, overall divorce rates in England and Wales have fallen to their lowest level since 1981 – there were 11.9 divorces for every 1,000 married people in 2007.

While analysts praised the growing durability of marriage, they pointed out that this has come about because fewer couples are choosing to tie the knot, with only the most committed doing so. Marriage rates are now the lowest since records began in the 1850s.

Michael Buchanan, the twice-divorced author of a new book called The Marriage Delusion, commented: “In previous centuries, people would get married early, have children and then be parted by the death of one or other, usually within a decade or two. Nowadays they can expect to live for four to five decades after marriage. It’s unrealistic to expect most people to sustain love and interest in each other for such long periods, especially if their children have grown up and moved out.”

Our firm acts for many clients who have been married for several decades; some have been unhappy in the relationship for almost as long, but have stayed because of the children or because they didn’t have the confidence to go it alone. Finally, however, they reach the decision to end the marriage and start their lives again.

On the other hand, opting out of a tired marriage after a few years might be ill-advised. Just because a relationship is no longer passionate or stimulating doesn’t mean it’s dead in the water. There is a lot to be said for feeling safe and comfortable with someone. Marriages, like friendships, go through phases – some better and worse than others. Your relationship might not be as wonderful as it once was – perhaps because children have taken the edge off it – but it doesn’t necessarily mean it is a failure. If you feel you’re going through the “itch”, sitting it out for a while might be the best option.

Marriages can get a second wind, especially when couples make a concerted effort to try to rejuvenate the relationship.