Relationship dynamics can influence sexual health outcomes and may affect engagement with HIV prevention strategies. This qualitative study explored how women's perceived relationship dynamics impacted their HIV prevention strategies, including condom and Pre-Exposure Prophylaxis (PrEP) use, and HIV testing. Semi-structured interviews were conducted with 34 women at higher risk of HIV acquisition and 40 women living with HIV in the USA, recruited through social media and health clinics. Interviews were audio recorded, professionally transcribed, and analysed using content analysis to identify themes. Participants identified trust, infidelity, and communication as the most salient aspects of their relationships that impacted HIV prevention. Trust fostered emotional security, while infidelity heightened uncertainty about partners' HIV status. Barriers to open communication with partners hindered women from prioritising their health. Participants recommended routine HIV testing with partners, open discussions about sexual health history, and PrEP to protect their health within relationships. The study offers valuable insights to inform the design of tailored HIV prevention strategies for women.