This study revisits the question of “who marries whom” by examining detailed patterns of racial and educational assortative mating across newlywed different-sex and same-sex couples in the United States. Against the backdrop of growing racial diversity, driven largely by recent immigration from Latin America and Asia, and the expansion of higher education, including graduate degrees, the author asks what boundaries are being crossed and for whom. Using nationally representative couple-level data from the 2013 to 2023 American Community Survey, the author found that same-sex newlyweds, particularly male couples, were more likely to be interracial and educationally heterogamous than different-sex couples, with educational crossing more prevalent. Detailed pairing further reveals that White-Hispanic and, to a lesser extent, White-Asian unions primarily accounted for higher interraciality among same-sex male couples. Among same-sex couples, educational heterogamy often involved pairings among those with at least some college experience, such as bachelor’s and graduate degree pairs. These findings underscore how structural demographic shifts are reshaping new marital sorting and call for moving beyond binary measures of homogamy to capture how much, which, and for whom boundaries are crossed in the ongoing study of “who marries whom.”