Before they say, "I do," some couples are adding a social media clause to their prenuptial agreements.

Jupiterimages, ThinkStock

The deal basically serves as a Facebook and Instagram gag order, prohibiting certain online posts without the other party's approval.

Bari Weinberger, a divorce and family lawyer in New Jersey, said she's seen an uptick in the number of cases involving "social media prenups."

"They're kind of precluded from making any negative or insulting, embarrassing or unflattering comments, or posting pictures of the like, about each other," she said. "Sometimes they're precluded from posting photos of their children or about family businesses, or money or asset-related information."

The penalty for violating an agreement is usually monetary and can depend on each party's wealth.

Weinberger said the clause can also call for both spouses to participate in a "social media blackout" in the event of a divorce.

For couples who got married when social networking wasn't popular or a threat, they still have the option to cover the issue in a postnuptial contract.

At the Rose Relationship Learning Center in Ocean Township, psychotherapist Stacey Rose said the new phenomenon is not surprising because social media can be psychologically damaging for couples.

According to Rose, social media is yet another topic that's worth discussing - just like money and kids - before people decide to spend the rest of their lives together.

"What couples agree about in terms of posting and not posting is really important," she said. "Just add it to the list."