Acts of infidelity are violations of the exclusivity norm of close relationships, and some individuals engage in infidelity more than others. Previous studies show that individuals high in the Dark Triad, the malevolent side of personality, are more likely to engage in infidelity, however not much is known regarding the relationship of infidelity and benevolent personality traits, the Light Triad. This study (N = 309) aimed to examine the relations between dark and light side of personality traits and infidelity. Two separate regression analyses were conducted using the Dark Triad and the Light Triad as predictors of infidelity attitudes and infidelity behaviors. The results showed that psychopathy and Kantianism were significant predictors of infidelity attitudes, while only psychopathy emerged as the significant predictor of infidelity behaviors. The findings where the Dark and the Light Triad were simultaneously modeled shows that dark and light personality traits are separate constructs uniquely predicting infidelity attituded and for infidelity behaviors the malevolent may have more predictive power than the benevolent.