Oooyesss - This is a very important question and it's excellent that you are considering it now, as opposed to later down the line.
The very short answer is that people of different religious beliefs can marry and have an excellent relationship - IF they discuss everything about the difference and how they will work with (and around them) BEFORE they happen. For example, will the kids be raised in one religion or the other, or both or neither? What holidays will be celebrated? Discussing these issues beforehand insures that there will not be any major unexpected surprises due to different religious expectations on part of the couple.
Another important consideration is the degree of belief involved. Some people are so much into their respective religious belief that they simply cannot accept anyone of a different faith (at least not to marry). People who are less religious generally have an easier time adopting and compromising on these issues because they have less emotional and mental energy expended into maintaining and justifying their beliefs.
This does not exclude people with extremely different religious beliefs from having a very happy, loving and nurturing relationship. A large measure of compromise is needed on both sides and the relationship has to be very solid in order for such a marked disparity to work.
It has been mentioned above (and I may have mentioned once or twice - :) ) that I am an atheist. The idea of a supreme being is silly to me, and actually anathema as I feel it produces and maintains many of society's major problems. My wife on the other hand is strictly Jewish Orthodox.
Obviously, these two beliefs are mutually incompatible. Yet we love each other so much that we worked out a system where we can be true to our beliefs (for the most part) and still keep the other person happy.
I "celebrate" the sabbath, by not doing anything my wife considers inappropriate, such as working on the computer when she and the kids are around. She however, knows very well, that as soon as she and the kids are asleep, I'm on the computer, or on the phone, etc. It's a compromise both ways. She respects my atheism and I respect her belief. We accomodate each other to as great an extent as possible.
You can love and respect a person even if you feel their belief is silly - and that's a great thing b/c she thinks atheism is silly and cannot fathom it, just as I cannot fathom the willing suspension of disbelief required by religion.
We are raising our kids Jewish - meaning that they go to a Hebrew school. However, we also talk to them at lenght about religion of all types and the positive and negative about not only the practice but the belief itself. Our kids are exposed to ideas that many of their classmates are not fortunate to experience.
Ultimately, they will make up their own mind as to what they believe. But, surprise! Kids do that anyway. We're exposing them to different sides of the question so they can make a more informed decision.
I am certain that even the act of questioning religious observance and the existence of god will be a positive experience and teach them critical thinking skills no matter what they ultimately choose to believe.
Again, it can work - just work out the details ahead of time.
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