Dated a devout Catholic. I said I'd learn what the Catholic Church had to say about itself. Read the Catechism, stuff from Vatican I + II, Trent, lots of papal bulls, the Church Fathers. By the end of it I knew more about Catholicism and church history than 99% of Catholics and quite possible her priest (given I used to call him out on stuff and he'd have to grudgingly admit he had no answers).

The Church is historically full of logical contradictions and the doctrine has more holes than Swiss cheese. It blew my ex's family's minds when I told them I wasn't Catholic precisely because I did know Catholic doctrine and Church history. Needless to say, we're not dating anymore.