In a fascinating study, divorce was found to be contagious. According to a study at the Framington Heart Study, a person whose friend or sibling gets a divorce is more likely to get divorced
As detailed in the study , the researchers found that:
Divorce is the dissolution of a social tie, but it is also possible that attitudes about divorce flow across social ties . . . We find that divorce can spread between friends, siblings, and coworkers, and there are clusters of divorcees that extend two degrees of separation in the network. We also find that popular people are less likely to get divorced, divorcees have denser social networks, and they are much more likely to remarry other divorcees.
The "contagious" nature of divorce is unlikely to be caused by shared environmental factors because friends who live far away are just as influential as those who live close by. But, having children mitigates the susceptibility to being influenced by peers who get divorced
The study concludes that attending to the health of one’s friends’ marriages serves to support and enhance the durability of one’s own relationship, and that divorce should be understood as a collective phenomenon that extends far beyond those directly affected.