The dark triad traits can be harmful in relationships from "summary" of Dark Psychology by Jonathan Mind
The dark triad traits, consisting of narcissism, psychopathy, and Machiavellianism, can have detrimental effects on relationships. Individuals who exhibit these traits tend to prioritize their own needs and desires above those of their partners. Narcissists are known for their self-centeredness and lack of empathy towards others. They often manipulate their partners for personal gain and seek admiration and validation from them. This can lead to feelings of neglect and emotional abuse in the relationship. Psychopaths lack remorse and guilt, making it difficult for them to form genuine emotional connections with their partners. They may engage in deceptive and manipulative behaviors, causing harm and distress to those around them. Their inability to empathize with their partners can result in a lack of emotional support and intimacy in the relationship. Individuals high in Machiavellianism are characterized by their cunning and deceitful nature. They often use manipulation and deception to achieve their goals, even at the expense of others. In relationships, this can lead to dishonesty and betrayal, eroding trust and creating a toxic environment.- The presence of dark triad traits in a partner can have serious implications for the health and well-being of a relationship. It is important for individuals to be aware of these traits and their potential impact on their relationships, in order to protect themselves from harm and seek out healthier connections.