In this work, we analyze two large-scale surveys to examine how individuals think about sharing smartphone access with romantic partners as a function of trust in relationships. We find that the majority of couples have access to each others' devices, but may have explicit or implicit boundaries on how this access is to be used. Investigating these boundaries and related social norms, we find that there is little consensus about the level of smartphone access (i.e., transparency), or lack thereof (i.e., privacy) that is desirable in romantic contexts. However, there is broad agreement that the level of access should be mutual and consensual. Most individuals understand trust to be the basis of their decisions about transparency and privacy. Furthermore, we find individuals have crossed these boundaries, violating their partners' privacy and betraying their trust. We examine how, when, why, and by whom these betrayals occur. We consider the ramifications of these boundary violations in the case of intimate partner violence. Finally, we provide recommendations for design changes to enable technological enforcement of boundaries currently enforced by trust, bringing access control in line with users' sharing preferences.

翻译：本研究通过分析两项大规模调查，探讨个体如何将智能手机访问权限分享视为恋爱关系中信任的函数。研究发现，大多数伴侣可以相互访问对方的设备，但可能对这种访问的使用方式存在明确或隐性的边界。通过考察这些边界及相关社会规范，我们发现对于恋爱关系中理想的智能手机访问程度（即透明度）或限制程度（即隐私性）缺乏普遍共识。然而，人们普遍认同访问权限应当相互且基于双方同意。多数个体将信任理解为他们关于透明与隐私决策的基础。此外，研究发现个体会跨越这些边界，侵犯伴侣隐私并违背信任。我们深入考察了这些背叛行为的发生方式、时机、原因及实施主体。在亲密伴侣暴力情境下，我们探讨了此类边界侵犯行为的后果。最后，我们提出设计改进建议，通过技术手段强化目前仅依靠信任维持的边界，使访问控制机制更符合用户的共享偏好。