Married women in India are increasingly at risk of HIV, often due to their husbands' extramarital sexual behaviour. Topical microbicides may provide protection to women who are unable to negotiate condom use. During the formative phase of a study to develop measures related to microbicide acceptability, we conducted in-depth interviews with 14 'high-risk' and 16 'low-risk' married women and 15 husbands. Some participants had recently completed a 2-week microbicide safety trial. A sequence of in-depth interviews with each participant explored the context of microbicide acceptability, including perceptions of couple harmony, vulnerability to HIV, sexual power, and ability to control life events. Women's perceptions of control and sexual power influenced attitudes towards microbicide use. HIV risk was most commonly associated with partner infidelity and easily detected, according to both men and women, by a lack of marital harmony. Despite this, high-risk women denied perceiving HIV risk until confronted with specific evidence of a husband's positive HIV or STI diagnosis. This study provides an in-depth examination of HIV risk for Indian married women, identifying potential determinants of microbicide use, and providing guidance for the development of psychometric scales to measure couple harmony, HIV risk perception, and sexual power and control.