Marriage generally improves life expectancy, but the age gaps between a couple affects the life expectancy of men and women very differently.

The secret to a longer life is to marry someone of the same age, at least if you are a woman. Marrying an older man shortens a woman’s lifespan, but having a younger husband reduces it even more, the greater the age gap between a woman and her husband, the shorter her life expectancy, regardless of whether he is older or younger.

According to Drefahl’s report in the journal Demography, a man who is between seven and nine years older than his wife has an 11% lower mortality rate than a man whose wife is the same age as him. However, a woman who is between seven and nine years older than her husband has a 20% greater mortality rate than if she were with a man the same age.

Some explanation may lie in the quality of friendships men and women form throughout life. Women tend to have more close friendships outside marriage and so benefit less than men from having a partner.

"Unlike the benefits of a younger wife, a younger husband wouldn’t help extend the life of his older wife by taking care of her, going for a walk with her and enjoying late life together. She already has friends for that. The older man, however, doesn’t,” Women with much younger husbands may die younger on average because they experience more stress.

Well the obvious advantage in taking a younger life partner is, of, course, that you are unlikely to be left a widow unless the object of your affection has the misfortune and spectacular bad luck to get run over by a bus on day three of the honeymoon or something equally tragic, not to mention inconvenient.

Getting left behind to cope alone is of course the most worrying thing older women have to face. Those with husbands considerably older than themselves dread the day when they will have to join hobby groups en masse to get through the day, or start line dancing classes, water colour groups or, God help us all, knitting circles.

Another drawback is financial insecurity. Unless both partners have a career, the man might find himself having to budget for the retirement of his wife extending well beyond his own.

Not everybody is sensible enough to work out such arrangements satisfactorily and a widow may find herself with serious cash problems at a time in her life when she is least able to cope with them. More often than not, women married to far older men find themselves nursing a sick husband at the end of his life instead of enjoying hers.

The solution is definitely to marry someone considerably younger than you, but the question is - how young? One reads of grandmothers successfully marrying young men of eighteen or nineteen years old but I have to say I cannot understand why such unions succeed. What on earth do they find to talk about? No, that definitely would not suit me.

For those of us who are not married, remember that committing a mistake is not a problem but repeating it.

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