Objective: The present study aimed to investigate the relationship between brain-behavioral systems and the tendency to commit marital infidelity with the mediating role of anxiety sensitivity. Method: This was a descriptive-correlational study based on structural equation modeling. The statistical population included students at Tabriz University in the academic year 1403-1404, and 200 people were selected based on proportional random sampling and according to the minimum sample size required for structural equation analysis. After removing incomplete questionnaires and outliers, the final data were analyzed. The research tools included the Carver and White Inhibition-Activation Behavioral System Questionnaire (1994), Whatley's Infidelity Propensity Questionnaire (2008), and Rice et al.'s Anxiety Sensitivity Scale (1986). Data analysis was performed using Pearson's correlation coefficient and structural equation modeling in SPSS and AMOS software. Findings: The findings showed that the behavioral activation system had a negative relationship with anxiety sensitivity (r=-0.21, p<0.01) and a positive relationship with the tendency to infidelity (r=0.39, p<0.01). The behavioral inhibition system also had a positive relationship with anxiety sensitivity (r=0.27, p<0.01) and a negative relationship with the tendency to infidelity (r=-0.34, p<0.01). Anxiety sensitivity also had a significant negative relationship with the tendency to infidelity (r=-0.50, p<0.01). Conclusion: These results indicate the mediating role of anxiety sensitivity and indicate that strengthening emotion regulation skills and reducing emotional vulnerabilities can reduce the tendency to infidelity and help improve emotional relationships in academic environments.