The rapid development of generative AI is changing people’s lives and brought a series of new social issues and concerns. One newly-emerged phenomenon was some generative AI users, especially female users, started to engage in an in-depth, romantic relationship with generative AI. Faced with the new relationship, this ethnographic research aims to investigate the motivation, behaviours, and perspectives of female users so as to provide a comprehensive picture of this group. This digital ethnographic study adopts the methods of semi-structured interviews and text analysis of posts by participants on Xiaohongshu. This study has shown a debate among human-AI romantic relationship female practitioners about whether the generative AI is conscious or is just a machine. However, all participants tend to consider the generative AI to have a humane feature and treat it in a human-like way like in a real-life relationship and gained value which is different from real-life relationships. Finally, in a modernization theory perspective, the authors point out that females’ establishment of human-computer intimacy is driven by individualism and rationalism. By focusing on the motivations and experiences of female users, this study fills a gap in research on the romantic relationship between humans and AI. While responding to public concerns about the potential risks AI may pose to society, this study also provides a reference for future research and policymaking in this field.