Background: The phenomenon of marital infidelity is a painful experience for the other party, which can make a person suffer psychologically. A review of research shows that women affected by infidelity have problems in terms of marital loneliness, emotional Divorce, Alexithymia, and psychological capital and need special attention for psychological interventions. Aims: The present study was conducted with the aim of determining the effectiveness of emotion-focoused therapy on marital loneliness, emotional Divorce, Alexithymia, and psychological capital in women affected by infidelity. Methods: The research method was semi-experimental with a pre-test and post-test design with a control group and a follow-up test period. Among the women affected by marital infidelity in Tehran in 2022, 30 people were selected as available research samples according to the inclusion criteria and randomly replaced in two experimental and control groups. The tools used in this research included marital burnout questionnaires (Pines, 1996), emotional Divorce (Gutman, 2001), Alexithymia (Begby et al., 1994) and psychological capital (Luthans et al., 2007). Data were analyzed with SPSS 23 software and analysis of variance with repeated measures. Results: The findings showed that there was a significant difference between the mean of the pre-test and the follow-up test of the experimental and control groups in terms of marital Burnout, Emotional Divorce, Alexithymia, and psychological capital. In other words, EFT reduced marital Burnout, Emotional Divorce, Alexithymia, and increased the psychological capital of women affected by marital infidelity (p<0.001). Conclusion: Based on the findings, it can be concluded that emotional therapy is effective in improving marital boredom, emotional Divorce, Alexithymia, and psychological capital, and this therapy can be used to improve the psychological status of women affected by marital infidelity.