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Abstract                
Background & aim: Marital infidelity is considered to be one of the most important traumatic factors for couples and families, and it is also a prevalent phenomenon for family and marital therapists. One of the consequences of marital infidelity is rumination in the spouse affected by infidelity. The present research was conducted by the aim of investigating the effectiveness of group compassion-focused therapy on rumination in women affected by marital infidelity.
 
Methods: The current research was a semi-experimental study conducted by pretest-posttest and follow up with control group design. The current research population included all the women affected by marital infidelity who referred to Rastin, Aram, Taranom, and Baran psychological and counselling services centers in Gorgan, Iran, in 2019. The research sample composed of 24 women who were selected by purposeful sampling method and were put into experiment and control groups by random assignment method (12 subjects per group). Both groups were assessed using Nolen-Hoeksema and Morrow’s ruminative response scale in pretest, posttest, and follow up stages. Group compassion-focused therapy was provided in 13 120-minute sessions for participants of the experiment group. The subjects of the control groups did not receive any intervention until the end of the follow up stage. The data were analyzed by variance analysis test with repeated measures in SPSS.
 
Results: Mean and standard deviation of the scores of rumination in the subjects of the experiment group were 58.08±2.84 in pretest, 52.50±5.74 in posttest, and 49.50±5.35 in the follow up. In the control group, mean and standard deviation of the scores of rumination were 59.08±0.92 before the intervention, 57.67±1.82 after the intervention, and 58.25±1.96 one month after the intervention. Results of the variance analysis with repeated measures indicated that group compassion-focused therapy has significantly reduced rumination in the intervention group in posttest and follow up stages (p<0.01, F=21.33).
 
Conclusion: Results of the present research confirmed the effectiveness of compassion-focused therapy in reducing rumination among women affected by marital infidelity. Family counsellors and therapists can use this therapeutic model for reducing the traumas caused by marital infidelity.