Purpose: Sex education should be given priority to address dating violence. Comprehensive sex education has been developed based on a nonviolent communication model between couples for the smooth resolution of problems with the opposite sex. The purpose of this study was to develop and apply Comprehensive Sex Education for unmarried couples in their 20s-30s and to examine the effects on sex communication, problem-solving communication, and relationship competence. Methods: This study developed a total of six web-based sex education sessions. A comprehensive sex education program combined with nonviolent communication between couples was developed based on the UNESCO Sex Education Guidelines. A pre- and post-equivalence control design was used to provide moderation-based sex education to compare the effects on gender communication, communication dissatisfaction, and relationship development. Results: We developed a comprehensive sex education program for couples that took three minutes per episode, on a web-based basis. Sex communication, problem-solving communication, and love relationship competence showed significant pre- and post-test differences between the experimental and control groups. Conclusion: The program of this study is an attempt to introduce Korea to comprehensive sex education, which has already been shown to be effective through numerous verification processes abroad and will provide assistance in forming future relationships between lovers.