I need to start by saying that my faith was pretty rocky when this happened and it was just the last straw. If my faith had been strong one nasty priest would not have had the same effect. It happened in the very conservative Ireland of the 1960s.
I was 20 or so and attending mass some time around 1964. The priest who was saying mass got up in the pulpit. At some point he said that he would prefer to see any close relative of his dead and in a coffin there, pointing to the area in front of the altar, rather than see them in a mixed marriage. To Catholic, a mixed marriage is one where a Catholic marries a non Catholic.
It so happens that, just on my father’s side, it took three mixed marriages for my father to be born. My paternal grandparents and all my paternal great grandparents were in mixed marriages. I stood up and started to leave. The rest is a fog in my memory. The priest said something and someone tried to stop me. I left and never returned except for the odd wedding or funeral.
In 1960s Ireland that was a big deal though not so much in Dublin. Many would have agreed with the priest.
A few years on I got married in a registry office to an American non Catholic. The aunt whose favorite nephew I was changed her will. Some of my friends were forbidden by parents to attend though, as far as I know, they all did. It was a great wedding and people still talk about it. Almost every attendee was a musician of some sort.
Here is a picture from the wedding.