That's exactly what it is. For every Asian woman who marries a white or black man, there's (statistically) an Asian man who has to either marry a white or black woman or remain single. Likewise, for every black man who marries a white or Asian woman, there's a black woman who has to marry a white or Asian man or remain single.
Now, it's true that for every Asian woman who marries interracially, there has to be a white or black man who also marries interracially, but in practice, having a large white majority population means that proportionally fewer whites have to marry interracially to really muck up the proportions among minorities.
Statistically, Asian men and black women tend to remain single as Asian women and black men tend to marry interracially. One possible interpretation is that there's kind of a continuum:
Black White Asian
where women interracially marry to the left and men interracially marry to the right. But it doesn't loop around.
Now, it's true that for every Asian woman who marries interracially, there has to be a white or black man who also marries interracially, but in practice, having a large white majority population means that proportionally fewer whites have to marry interracially to really muck up the proportions among minorities.
Statistically, Asian men and black women tend to remain single as Asian women and black men tend to marry interracially. One possible interpretation is that there's kind of a continuum:
where women interracially marry to the left and men interracially marry to the right. But it doesn't loop around.