Are prenuptial agreements forbidden?

The Catholic Church teaches that marriage is the complete, lifelong, and exclusive commitment between a man and a woman who are free to marry. Consequently, any prenuptial agreement that anticipates divorce—and the division of property between spouses should a divorce take place—invalidates the marriage commitment made between a man and woman, because their agreement denotes deficient consent by one or both of the prospective spouses, namely, by excluding the essential property of indissolubility (CIC, canon 1056; see CCC 1625-1628; 1639-1640).

A legitimate exception would be a prenuptial agreement made to protect inheritance rights for children from a previous marriage, e.g., in the case of a widower marrying a never-married woman.