In a survey of 1,313 men reporting on 2,465 partnerships recruited at beer halls in Harare, Zimbabwe, 2.5% met a definition of "sugar daddy": men with a non-marital partner at least 10 years younger and under 20 years old, and exchanged cash or goods for sex. Men engaging in intergenerational sex with a teenage woman had similar HIV prevalence, incomes, and condom use as men in other partnerships. Most men (62.3%) had partners 5 or more years younger, with wider age gaps in longer-term relationships. Condom use was less common within married and steady partnerships compared to casual and more common with younger women. The most common form of intergenerational sex, with the widest age gap and lowest condom use, occurs within marriages and steady partnerships. Such "conventional" intergenerational sex may play the pivotal role in sustaining a generalized epidemic across generations and present the most difficult challenge to prevention.