The researchers have called it “divorce clustering” and say that a split up between immediate friends increases your own chances of getting divorced by 75%. The effect drops to 33% if the divorce is between friends of a friend, what the researchers call two degrees of separation, then disappears almost completely at three degrees of separation. It is not only the marital status of friends but also siblings and colleagues which has a significant effect on how long your own marriage might last. Breaking up will catch on among your friends, and the more divorcees you know, the higher your own chances of becoming one.

The research comes from sociologists and psychologists from three North American universities who have examined statistics from a group of individuals over a 32-year period. They looked at the effect of divorce among peer groups on an individual’s own risk of divorce and found a clear process of what the scientists called “social contagion”. The study was carried out by academics Rose McDermott at Brown University, James Fowler at the University of California and Nicholas Christakis at Harvard.