The purpose of this study is to understand the characteristics of nonmarital cohabitation in Korea, which has not been extensively researched yet. The current study seeks to understand the societal atmosphere and changes related to marriage or nonmarital cohabitation by examining people's attitudes towards them. Additionally, the study aims to shed light on the characteristics of nonmarital cohabitation by utilizing data obtained directly from individuals who have experienced it. This research takes this into consideration and explores the childbirth, attitudes towards children, and family-related perspectives of individuals who choose nonmarital cohabitation. Furthermore, the study examines the institutional desires of individuals who have experienced nonmarital cohabitation in Korea. Additionally, the study reviews relevant international institutions and investigates the experiences and opinions of institutional users. Finally, by synthesizing the research results, this study summarizes the characteristics of nonmarital cohabitation in Korea and seeks implications for the policy development related to nonmarital cohabitation in Korean society.