My last GF several years ago was a Christian. I didn't have problems with her religion-wise because she didn't take religion very seriously.
But I always had problems with Christians who take the religion or the denomination very seriously. The problem is their persistence of trying to get you into their side....I've been on their side for 20 years man and found fatal flaws in their beliefs and I'm not going back again. If I do, I'd only be pretending.
....Imagine if you were married to that. Naturally, they would also want someone to talk to who can reciprocate their beliefs.....I cannot provide that.
I used to have friends who are serious Christians but they are not my friends anymore. My parents are serious Christians and are always concerned and frustrated about me all the time. At times I had to pretend so I don't worry them too much. Because they believe I'm going to hell if I don't change.
I've seen it, lived with it for a long time. I most certainly don't want to get married to it!