The phenomenon you described can be attributed to various psychological and emotional factors, and it's important to note that not everyone behaves the same way in such situations. However, there are several possible reasons why some people who cheat become upset when they discover their partner has cheated:
Double standards: Some individuals might have a sense of entitlement or believe that they are exempt from the same rules they apply to their partner. They might rationalize their own actions but hold their partner to higher standards, leading to a discrepancy in their reactions.
Guilt and shame: Cheating can lead to feelings of guilt and shame, especially if the individual knows that their behavior is morally wrong or harmful to their partner. When they discover their partner has cheated, it can trigger a defensive response to avoid facing their own guilt and deflect responsibility.
Fear of losing control: Cheating can provide a sense of power or control for some individuals, and they may struggle with feelings of vulnerability or loss of control when they find out their partner has also cheated. This can lead to strong emotional reactions like anger and frustration.
Jealousy and insecurity: Cheating can sometimes stem from feelings of insecurity or a desire for validation from others. When they learn their partner has cheated, it can intensify their own insecurities and trigger feelings of jealousy and a fear of being replaced.
Ego and self-image: Some people may tie their self-worth to their ability to attract or maintain the loyalty of their partner. Discovering their partner's infidelity may threaten their self-image, leading to emotional distress.
Lack of empathy: Cheating can be driven by a lack of consideration for the emotional impact it may have on their partner. When the tables are turned, they might not fully empathize with their partner's pain because they failed to recognize the pain they caused themselves.
Emotional investment: Despite cheating, many individuals may still have emotional investment and attachment to their partner. Learning about their partner's infidelity can evoke feelings of betrayal and disappointment, amplifying their emotional response.
It's essential to remember that each individual and relationship is unique, and people's reactions can vary widely. Some people may feel genuine remorse for their actions and recognize the hurt they caused their partner, while others may react defensively or attempt to justify their own behavior. Open communication, empathy, and seeking professional support, such as couples therapy, can be valuable tools for working through the complex emotions surrounding infidelity in a relationship.