Background and Purpose: Sexual addiction includes actions, imaginations, and sexual attitudes It's very difficult to control it for a sex addict, and this leads to serious issues in their individual and social life. The present study, entitled Understanding Sexual Addiction in Connection with the Self-Concept of Sexual Addicts, seeks to examine the categories that have been formed in the experience of sex addicts. Materials and Methods: The method used in this research is qualitative and has been used in the research process from Grounded Theory. Data were collected using participatory observation method and deep interview technique. Finding: According to the purposeful sampling method and theoretical sampling and theoretical saturation criterion, 40 sex addicts participated in the research. According to the findings of this research, four categories including "fidelity and consolation, imposed isolation, self-reflection, and unstable trust" were developed. The results of the study showed that the sexual activity of addicted sex addicts is strongly influenced by their experiences and family-environmental interactions that this sexual activity has been exacerbated by the continuing illiteracy of the sex addicts due to the poor functioning of other social institutions such as educational and legal institutions. Discussion: Accordingly, four categories of research data were tied around the core of the "negative self-concept reinforcement sex addiction" core.