The phenomenon of cohabitation or living together without a legally recognized marriage has become one of the social issues developing in modern society. Changes in values, cultural development, economic factors, and shifting understandings of commitment and marriage have contributed to the increasing practice of cohabitation. In the Indonesian context, this phenomenon generates debate because it encounters legal, religious, and cultural norms that consider marriage as an important institution in human life. This study aims to analyze the phenomenon of cohabitation through Martin Buber’s dialogical philosophy, particularly the concepts of the I-It and I-Thou relations. This research employs a qualitative method with a library research approach by analyzing Martin Buber’s works and various literature related to cohabitation, marriage, and human relations. The findings indicate that cohabitation cannot merely be understood as a legal or moral issue but also as a philosophical issue concerning the quality of human relationships. From Buber’s perspective, relationships oriented only toward personal needs, comfort, or specific interests tend to become I-It relations because the other person is reduced to an object. Conversely, the I-Thou relation emphasizes respect for personal dignity, openness, responsibility, and authentic encounters between individuals. Therefore, Martin Buber’s thought provides a critical reflection that human relationships should be built upon dialogue, responsibility, and respect for others as complete and valuable persons.