What are the requirements for a mixed marriage?
Entering a mixed marriage is highly unadvisable. Speaking as one who has had personal experience with them (having been the then-Protestant member of a marriage with a Catholic), mixed marriages always involve pain for both of the parties unless neither spouse cares about religion. These problems can be very grave, threaten the survival of the marriage, and may not emerge for years (as, for example, when the children reach the age of being religiously educated and one partner changes his or her mind about the agreements that were made about the children at the beginning of the marriage). For this reason, whenever people ask me about mixed marriages, I always tell them that the non-Catholic party should seriously look at the Catholic faith and the possibility of becoming Catholic. Simply on a human level (quite apart from the benefits to the person’s soul), this solves an enormous number of problems that would otherwise plague the marriage. I therefore invite any non-Catholic who is con