There seem to be many, many forer@s here who are (or were) married, or in a serious relationship, with someone from a different culture.
Looking at all of us, we should have some really interesting stories about how we got around the potential misunderstandings and different habits.
From the Canadian - Bolivian perspective, a big issue was the completely different perception of time.
One phrase that gave me no end of trouble was "I'll call you tomorrow". I'd hear this, take it literally, and hang around the phone in a love-induced fog waiting for a call. It took a long time to learn that the Bolivian translation of this was "If I'm still in the same mood I'll call you tomorrow ... or maybe the day after .... or next week ...." As a result I thought my boyfriend at the time was completely unreliable, and he thought that I was completely anal.
I could go on, but I'd rather hear your stories than tell mine ....