Our study reports the results from a mixed method study comparing age-similar (AS) marriages of orphaned young women to age disparate (AD) marriages, defined as spousal age difference of 5 or more years. Research in Zimbabwe and sub-Saharan Africa suggests that AD sexual relationships between older men and young women increase the risk for HIV but few studies have examined this association among married couples or explored why young women marry much older men. In this study, a total of 35 orphaned young women aged 17–26 years in rural Zimbabwe participated in semi-structured interviews during 2012–2013. Twenty-four were in AD marriages and 11 AS. All had participated in a 5-year HIV prevention trial, during which they had married and dropped out of school. We examined two research questions: were AD wives more likely than AS to cite economic considerations as a reason to marry, and were AD marriages associated with different health and economic outcomes compared to AS? Our results showed that the reasons the women married were essentially the same among the two groups; economic considerations for marriage were uncommon. Nevertheless, AD wives generally fared somewhat better than AS wives on economic and well-being measures. HIV prevalence was similar; however, the AD group accounted for all five cases of herpes simplex virus-2. Findings suggest the complexity of sexual and reproductive health in rural Africa, where AD marriages are common and accepted. The challenge for primary prevention is to develop strategies to mitigate the risk of sexually transmitted infections, as well as the potential abuse of young women, within the appropriate cultural context.