This study examines the politics of infidelity discourse in Netflix’s The Crown, using Multimodal Critical Discourse Analysis (Kress & van Leeuwen, 2006) and Judith Butler’s (1990) theory of gender performativity. It focuses on the relationship between Prince Charles and Princess Diana. This paper investigates how the interplay of verbal and visual elements with gender-performative roles helps define marital infidelity as an institutional, rather than a purely personal, failure. Findings show that Prince Charles's infidelity is discursively constructed as an act of institutional escape and masculine re-signification, in contrast to Princess Diana’s responses, including her public dancing, her audio confessions, her revenge dress, and her BBC interview, which are constructed as subversive repetitions that expose and destabilise the gendered script of the royal marriage. This study argues that The Crown uses multimodal storytelling to demonstrate that infidelity is a gendered and institutionally imposed performance rather than a moral transgression.