The motivations behind a psychopath's actions can be complex and may not necessarily follow conventional patterns of reasoning. In the scenario you described, there could be several possible motivations for a psychopath to say they know they will never be good for you but still want to stay in the relationship:
Control and Manipulation: By admitting they are not good for you, the psychopath may be attempting to gain a sense of control over the relationship. They could be using reverse psychology, making you feel like you have to prove them wrong or that you can "fix" them, thereby increasing their influence over you.
Emotional Leverage: This statement could be a way for the psychopath to gain emotional leverage over you. By expressing vulnerability and self-awareness of their flaws, they might hope to elicit sympathy and make you feel responsible for their well-being, keeping you emotionally invested in the relationship.
Preventing Rejection: The psychopath may sense that you are becoming aware of their manipulative behavior or that you might consider leaving the relationship. By acknowledging their flaws and making you believe they genuinely want to change, they could be trying to prevent you from leaving or protect their source of emotional validation and control.
Maintaining the Relationship for Personal Gain: Psychopaths often prioritize their own needs and desires above others. They might want to keep the relationship intact because it serves some personal advantage, such as financial support, social status, or a consistent source of admiration or attention.
Avoiding Accountability: By preemptively admitting their shortcomings, the psychopath may attempt to preempt accusations or criticism from you or others. They could use this admission as a defense mechanism to deflect blame or avoid facing consequences for their harmful actions.
Playing Mind Games: Psychopaths can be adept at playing mind games to confuse and disorient their partners. This statement might be just another tactic to keep you off balance and uncertain about the true nature of the relationship.
It is crucial to remember that psychopaths are skilled manipulators who can be highly deceptive in their words and actions. If you are in a relationship with someone you suspect may be a psychopath or displaying manipulative behavior, it is essential to prioritize your own well-being and seek support from friends, family, or a mental health professional who can provide guidance and help you navigate the situation safely.