I think the cultural differences do add to the marital strains in a marriage. Whenever we argument, it seems to just add to it that I am in a foreign country and feel even more foreign b/c I can't just leave if I want to. In general, it's more that I am in a foreign country, with a different culture than actual differences btwn us. He's a very communicative and expressive person with me, so that's not an issue.
More that I am painfully aware that I don't have my family and friends here to support me when I need them most. Sometimes I dream about the day that we move to the US and he is the foreigner just so he has an idea what it's like. Mind you, I've been 2 yrs now and still get homesick, not that I don't like living here, just that I miss friends/family and some things about the US.