Your morals don't match up, and the differences probably offend both of you. You have a hard time taking a live-and-let-live attitude about this, because they're such basic and important beliefs that are at odds. Your spiritual views are likely to be completely different, and instead of respecting each other's beliefs, you both probably cling even more fiercely to your own as if they're the only acceptable beliefs there are.
So who's right and who's wrong? That's just the problem -- neither one of you! These are your opinions, formed after a lifetime of experience and learning. To argue over them could be interesting, to a point, until things get ugly and you both throw up walls to avoid facing the fact that your own way of viewing things isn't the only one -- and it's not necessarily even the most well-founded, either. Education could also become a big issue between you, especially if you've reached different levels of it. And if you travel together, get ready for some major disagreements! Everything from which type of hotel you should stay in to where you should eat sparks discussions, at least, and more likely arguments. This aspect's intensity is determined by other aspects between you. If you communicate well and treat each other with respect, this isn't too hard to deal with, but if your communication is already afflicted, you have battles.