This is a comparative ethnographic study which explores the proposition that married women are placed uniquely at risk by: (1) the worldwide diffusion of an ideology of marriage as a relationship based on romantic love and companionship between equal partners (i.e. "companionate marriage"); (2) social contexts of persistent gender inequality; and (3) economic contexts of under- or unemployment and labor migration. The project's specific aims are: 1) to compare across five developing country sites (Papua New Guinea, Mexico, Vietnam, Nigeria, and Uganda) a) the relative penetration of ideas and practices associated with companionate marriage and b) the specific forms of marital and extramarital relationships; 2) to understand and explain the ways in which these ideas about and practices of intimacy are shaped and constrained by gender unequal structures and ideologies, local forms of economic organization, and cultural change; 3) to evaluate the implications of these ideas and practices for HIV prevention within and outside of marriage; 4) to use multi-sited comparative ethnographic research to generate findings of broad theoretical and public health significance; 5) to present research findings to appropriate local and international agencies and professionals in order to contribute to the development of gender-sensitive, culturally specific interventions to limit marital HIV transmission in each field site.