What would you do in my situation? Spiritually asking of course?

My best friend is Catholic. Not truly devout but he does pray sometimes and goes to m. He also wants to get married in the Catholic Church. I was raised Muslim but currently I lean towards a more agnostic/buddhist religion. We were talking with a few friends and a joke was made that we should get married. He mentioned that I would need to convert and I replied of course I'd convert. For this guy I would do it...uming we even got to that point(we are still purely friends). Would anyone, has anyone, converted to get married?