Social scientists followed participants in a study of risk factors for heart disease for thirty-two years.

And learned that divorce is a social condition. When divorce penetrates a social circle, it is much more likely to strike within that social circle again.

This finding confirms what many people likely observe around them.

The corollary is that where divorce has not yet penetrated a social circle, a first divorce within that social circle is less likely to occur.

Some ancillary findings.

Having children tends to counter social impetus toward divorce.

Remarriages are more likely to result in divorce than first marriages, with each successive walk down the aisle facing escalating risk of divorce.

Read more in this New York Times piece: Is Divorce Contagious? and this Huffington Post piece: Is Divorce Contagious?