Race really doesn't matter in a relationship, but one thing that does matter in a relationship is culture. People from different countries have different expectations of others, and while they are not always diametrically opposed, you both should have an understanding of each other's culture to have a happy and loving relationship.
I do think that race matters when it comes to personal preferences... I think I would be lying if I said it didn't... There are in fact, beautiful women all around the world, but people sometimes like a painting by one artist over the paintings of another... It all has to do with aethetics, and if for example someone's look is exciting and different to you, then this can make the relationship even more special because you come to love someone and their differences, and you notice the things like the bridge of their nose, or their ears, or their hair that you might have never paid attention to otherwise... it can definitely make your relationship very special.