Robust advancements in clinical treatment of people living with HIV (PLHIV) have resulted in the current "treatment as prevention" strategy: the inability to transmit the virus when it is undetectable. Nevertheless, disclosure within marital relationships remains important to adhere optimally to treatment and further limit transmission in the era of treat-all. Disclosure, however, can have serious social repercussions, particularly for women. This paper examines gendered disclosure decisions and their social consequences in marital relationships in Tanzania. Drawing from a 9-month ethnographic study in Shinyanga Region, we explore how Sukuma societal values shape disclosure decisions. In-depth interviews with 103 PLHIV and 19 FGDs inform our analysis. We found that societal values regarding gender and marriage significantly influence disclosure decisions in marital relationships. The HIV treat-all approach, with its focus on early treatment initiation preserved health and inability to transmit allowed men and women to carefully weigh the costs and benefits of disclosure to their marital aspirations. The benefits of antiretroviral treatment for social relations are often overlooked in medical interventions. We conclude that to reduce difficult disclosure decisions for PLHIV, emphasising community awareness of HIV treatment as prevention to mitigate the negative impacts of disclosure is needed.