Okay little one, let's talk about something called the "Petrine Privilege." It's a big fancy term that means if two people get married, and later one of them converts to a different religion, the Pope (the leader of the Catholic Church) can sometimes let them get an annulment.
An annulment is when the Church says that the marriage never really happened. It's like erasing it from history. So if one of the people wants to get remarried in the Church, they can because they are not technically still married.
The reason it's called the "Petrine Privilege" is because it comes from a guy named St. Peter who was one of Jesus' closest friends. He was the first pope, and the Catholic Church believes that he has the power to make decisions like this.
Now, not everyone can get an annulment through the Petrine Privilege. There are certain rules and circumstances that have to be met. But the basic idea is that if someone wants to get out of a marriage because their partner changed their religion, the Pope might be able to make that happen.