Appearing new forms of relationships before marriage among young people in recent years, the aim of this study was to discover the causes and motivations of people to choose this way of life. The qualitative methodology was selected as the dominant method. Snowball sampling helped to find samples. For data collecting, 23 men and women engaged in a cohabiting were interviewed in semi-structured manner. Results of the interviews were divided into several categories. Major of participants lived in Bandar Abbas, Kerman and Tehran. After analyzing the data with an interpretive approach, 7 main categories were elicited: relative satisfaction with relationship, poor mutual commitment, poor quality of relationship, fear of judgment of family and community, personal injury, transactional relationship and no decision to marriage. The slow and creeping spread of cohabiting relationships, high divorce rates, emotional and sexual infidelity, and the prevalence of Western-style relationships settled before marriage threaten all Iranian families. Solving these problems needs a serious commitment on the macro-level officials and experts to review the employment policy, economy, entrepreneurship, TV programs and cultural policies.