cross-cultural marriages work in some cases, perhaps better than same race/cultural marriages. for example, in our country, the divorce rate is lower for black women + white men, rather than white women + white men. actually, the same study showed that marriage where white women were involved almost always had a higher divorce rate (hopefully, sharing this statistic won't call all the pro-male champions and zealots from their hiding places/caves : D).
while the definition of "cross-cultural" is pretty wide to interpretation, but there are a myriad of factors that are far more important than culture -- and i wouldn't hold that concern any higher than the others, such as the expected predictors of successful marriage, such as communication, compatibility, support, blah blah.