A study at Rockefeller University in New York suggested that the stress of divorce could accelerate the ageing of white blood cells. On the other hand, life-long happiness really does what it says on the tin.

Experts believe that long-term loving relationships can keep you as much as 7.5 years younger. Admittedly regular sex and long-term relationships don't always go together, but you never know your luck.

Years added: 7.5