There's a fundamental difference between a believer and an atheist with regards to their outlook on life which for me would be incompatible with a relationship.

It would depend on exactly how religious they were. Fundamentalist zealot? Church only at Easter and Christmas because they were brought up that way? There's lots of in between there, I would hate to think I was so closed minded and miss out on a great person because I was being judgmental. It all comes down to respect.

RUN!!! Run fast and run far.

I have lived in such a marriage for 23 years. It is a satisfying marriage for both of us.

My preference of course is to be with some who is a non-believer like me, but I wouldn't exactly mind if my significant other was a believer as long as they wouldn't talk about it or try to convert or save me. A sparsely practising believer would be acceptable, but someone who goes to Church every Sunday and talks about God all the time wouldn't fly.

It doesn't matter, until it does.

If they're willing to respect me and mine, then it's only fair and decent that I do the same. If we're both willing to give it a fair shot why let a little thing like religion get in the way?

I guess it would depend how much they take their faith seiously. I wouldn't have a problem with someone who is a nominal believer or even someone who is open discuss their ideas and crititically look at them. I have observed that some very intelligent people just switch off their part of mind where they just don't want think about or challenge religion for their own convenience.

Diametrically opposed never gonna. I would be in constant contempt of her mindset

I have always refused to date anyone religious before. Until the last guy, who seemed "reasonable" and not overbearing in his belief, (at first) and was okay with my atheism...until he wasn't after awhile. I had to leave the relationship to keep my sanity. I guess some people could make it work. But I could not.

I would be honest and tell them that their belief in myths does matter to me.

My belief is that it matters—to me, the atheist. And, at the core, probably to the believer.

It’s rare that such a fundamental difference is surmountable, but not impossible.

To me, after a certain age a belief in something so obviously false is a sign of a simple mind. Deep down I can never really take them seriously. And if you don't respect the mind of the other, then there is no point.

An understanding and acceptance of differences can lead to a very healthy relationship. My children were introduced to religion so as to make their own minds up. They have since chosen to pursue Science though.
IT IS NOT A COMPETITION!!

Diametrically opposed never gonna. I would be in constant contempt of her mindset

My last ex was a believer and not too overboard with it, despite having a religious tattoo. We never had a single argument about my lack of belief vs. her belief (and, if we had, it probably would've been me that caused it). When we broke up, it was for reasons completely unrelated to religion

Well, I've been in one such situation for three months now. Even though we're able to converse freely, we mostly leave religion out of things. On Saturday nights, I ask him if he's "churching" in the morning. Sometimes he does, other times he chooses to work out with me. We each get to do our thing, separate, and together. We live nearby , in our own homes, so I get whatever alone time I need - and I need more than some. He respects that.
I will admit though - every now and then, I poke a little, and ask him how he knows his god is the best , or only one ...

Too soon to know if this is a novelty for us both, or if we might beat the odds ?

I got an interesting response from a good friend of mine about five years ago when i said to him that i wish i will find a woman who will be atheist or agnostic. Socialist or comunist and vegan or vegetarian. His response :: ok do you also want her with three breasts and a square but. Ha ha ha. Then he said they don't come like that as you are. So respect and understanding helps. Good luck.

I feel like it's a trap that will be short lived and ultimately backfires. I'd spend the entire time either wondering how they can be so wrong about reality and trying not to sound condescending while explaining how things actually work. You can be happy, it you can be right. You can't be both in that situation.

Good things can come in ugly packages, so I don't feel bad about it, but that doesn't mean I won't, at another moment, make the time to explain the existence of God(s) is not a logically necessary conclusion, and is made almost purely of arbitrary norms and memetics.

However, I don't think this will be a proactive scenario, I would do this as a response to false assertions about the nature of God(s), as a general , because it's foolish to think that people will just always listen and understand to what is being communicated to them, at any time. It simply does not work that way.

So people should know the truth, period. I hold my beliefs because I know they are both backed with sources, and necessary logical deductions and I certainly don't have to out anything for knowing the truth.