"Talking about privacy always feels like opening a can of worms.": How Intimate Partners Navigate Boundary-Setting in Mobile Phone Without Words

Mobile phones, as simultaneously personal and shared technologies, complicate how partners manage digital privacy in intimate relationships. While prior research has examined device-access practices, explicit privacy-rule negotiation, and toxic practices (e.g., surveillance), little is known about how couples manage digital privacy without direct discussion in everyday relationships. To address this gap, we ask: How is digital privacy managed non-verbally and across different media in mobile phones? Drawing on 20 semi-structured interviews, we find that partners often regulate privacy practices of privacy silence —the intentional avoidance of privacy-related conversations. Five motivations for leaving boundaries unspoken: perceiving privacy as unnecessary in intimacy, assuming implicit respect for boundaries, signaling trust and closeness, avoiding potential conflict or harm, and responding to broader societal and cultural expectations that discourage explicit privacy talk. We also identify a hierarchical grouping of content-specific privacy sensitivities, ranging from highly private domains (e.g., financial data) to lower-risk domains (e.g., streaming accounts), and show how these priorities shift across relationship stages. These findings show how silence, culture, and content sensitivity shape everyday boundary-setting and underscore the relational and emotional dynamics underpinning mobile-phone privacy management.