Background and objectives: Given the abnormal and unpleasant complications that accompany it, infidelity is a kind of disorder since it has irreparable consequences for the couples. The present study aimed to investigate the effectiveness of cognitive therapy intervention on the rumination of women affected by the male infidelity. Materials and methods: This single case experimental study used an Non Concurrent Multiple Baseline design. The study population included all couples affected by male infidelity referring to Ahvaz’s private and public counseling centers. Given the inclusion and exclusion criteria, oral interviews and women who scored higher than 55 in the rumination scale, 3 couples were selected targeted sampling and received therapy. Accordingly, 8 sessions of cognitive therapy were held individually once a week and each session lasted 90 minutes. The research tool was NolenHoeksema & Morrow Rumination Questionnaire. The data were analyzed using visual analysis (chart drawing) and clinical significance. Findings: According to the findings, women showed increased rumination (36.65%) and improved therapy (45.3%) in the follow-up phases. The findings showed that t was bigger than the table with a degree of freedom of 31. Therefore, it can be argued that normal and abnormal groups are not clinically different in terms of the variable of rumination. Therefore, cognitive therapy is able to decrease the rumination of women affected by the male infidelity. Conclusion: The results showed that cognitive therapy sessions can be decrease the rumination of women affected by male infidelity. Therefore, this therapy can be used to reduce the psychological suffering of women affected by male infidelity and improve the relationships in private and public counseling centers.

Infidelity, Cognitive-Existential Therapy, Rumination