As an example of what I meant: I would date someone with a different religious belief system than I if it had the same VALUES within it. Where it comes into conflict for me is if the values diverge greatly. So if the religion was an accepting one that encouraged tolerance, love, and understanding, which are my values, I could be far more accepting of it in a partner.
On the other hand if their spiritual beliefs were about control, exclusion, and judgement, I would really struggle with it.
However the beliefs are irrelevant to me- time travel, that God is a man in a cloud somewhere, that there are Gods and Goddesses that rule our choices and emotions, that there is no God. All of those sorts of things don't matter to me. It's how they are expressed that does.
Hope that clarifies a little