New Primary is Catholic

My long distance romantic interest and I have been talking on and off for two years, and we have been designing our relationship over time - the idea being that one of us will move when it becomes clear that we are staying together for the long term. The timing is right for both of us right now and we are both really excited to start dating with intention.

Because we are on the same page about everything else, I decided to ask about religion and discovered he is a devout Catholic, which I actually prefer over a non-religious person. It does beg the question, though…

Are there a lot of Catholics who embrace polyamory and ENM, given their more traditional definition of marriage and partnership? He is deliberately pursuing an open / cuckhold relationship with me and I don’t want him to wake up one day and realize it’s against his religion and wants to switch back to a monogamous relationship once the novelty wears off.

Does anyone here have experience with this?