Determinants of extramarital sex in the Philippines.

Understanding the factors associated with sexual behaviour is critical in slowing the spread of HIV in the Philippines, where sexual transmission accounts for most HIV infections, with the majority from heterosexual activity. Further, unprotected sex is common, as is sex with prostitutes. These factors increase the risks associated with extramarital sex. From an analysis of a nationally representative sample of women, we found that a number of factors were related to women's reports of their husbands' sexual activity outside their current relationship: women report that partners who are more educated, have been in the current relationship longer, and who had sex before marriage are more likely to be engaging in sex outside the marriage. Further, men who are older, who are farmers, who live at home, and who have more educated wives, were believed to be less likely to be having extramarital sex.