I converted to Christianity - from the default British religion of not really interested in anything - when I was 20. At first I was very zealous and tried to convert everyone around me, but I mellowed.
My conversion was very quick. I had not been searching for anything or aware of any lack in my life, but one single conversation with my new Christian housemates suddenly opened up a dimension I had not been aware of before. A couple of days later I realised that I was no longer an atheist - and I had been an utterly convinced one - and that there was “something” there. So I suppose that, being white British and having been brought up in a nominally Christian culture, I assumed that was the way to go. The rest is history, as they say - 38 years of it.
Some might interpret my story to mean that I was vulnerable or having a mental health crisis. I really don’t think I particularly was. I suppose I was vulnerable to some of the people I met afterwards who tried to school me into their particular interpretation of Christianity. But fortunately I still had a brain and didn’t follow anything hook line and sinker.
If my DH became Muslim it would be a huge surprise, because he has been Christian all his life - and I mean actively involved, not just nominally. But I would cope with it, as long as he didn’t try to get me to wear a Hijab or give up bacon. I think it’s extremely unlikely, though, because both of us now have fairly open theological views. I am happy to say that I am a Christian and you are a Muslim and they are a pagan, and all of us are trying to connect with Something bigger than ourselves. The Something I believe in - and know - is all about love and compassion, not judgement and exclusion. I think God cares a lot less about theology and the exact details of religious practice than human beings do.
I gave up believing in the concept of hell and eternal damnation a long time ago. My life is better for it.