Facebook CEO Mark Zuckerberg changed his status to “married” Saturday and received over one million “likes” from his followers. But the site he founded isn’t always so marriage-friendly. In fact, lawyers say the social network contributes to an increasing number of marriage breakups. More than a third of divorce filings last year contained the word Facebook, according to a U.K. survey by Divorce Online, a legal services firm. And over 80% of U.S. divorce attorneys say they’ve seen a rise in the number of cases using social networking, according to the American Academy of Matrimonial Lawyers. “I see Facebook issues breaking up marriages all the time,” says Gary Traystman, a divorce attorney in New London, Conn. Of the 15 cases he handles per year where computer history, texts and emails are admitted as evidence, 60% exclusively involve Facebook.

“Affairs happen with a lightning speed on Facebook,” says K. Jason Krafsky, who authored the book “Facebook and Your Marriage” with his wife Kelli. In the real world, he says, office romances and out-of-town trysts can take months or even years to develop. “On Facebook,” he says, “they happen in just a few clicks.” The social network is different from most social networks or dating sites in that it both re-connects old flames and allows people to “friend” someone they may only met once in passing. “It puts temptation in the path of people who would never in a million years risk having an affair,” he says. Facebook declined to comment.