There could be various reasons why a guy might want to see how you react to an ex wanting him back. Here are some possibilities:
Ego validation: Some individuals enjoy knowing that they are still desirable and sought after by others, even if they have no intention of getting back with their ex. Seeing your reaction can provide them with a sense of validation and boost their self-esteem.
Curiosity: The guy might be curious about your feelings and how invested you are in the relationship. By observing your reaction, he may get insights into your level of interest and emotional attachment.
Testing your feelings: He might want to gauge your feelings towards him and the relationship. By bringing up the topic of his ex wanting him back, he can assess whether you feel jealous, insecure, or possessive, which can give him clues about your emotional investment.
Jealousy: In some cases, the guy might intentionally try to make you feel jealous as a way of eliciting a reaction from you or to assess your level of commitment to the relationship.
Insecurity or seeking reassurance: If he has doubts about your feelings or the stability of the relationship, he might bring up his ex's interest to see how you respond and if you reaffirm your commitment to him.
Mind games or manipulation: Unfortunately, some people use mind games to test their partner's emotions or control them. This behavior is unhealthy and can indicate issues in the relationship.
Communication and trust: It's possible that he wants to have an open conversation about his ex's advances and share his feelings with you, fostering transparency and trust in the relationship.
Regardless of the reason, it's essential to communicate openly and honestly with your partner. If you feel uncomfortable or unsure about his intentions, express your feelings and concerns calmly and directly. Healthy relationships are built on trust, communication, and mutual respect, so it's crucial to address any issues that arise in a constructive manner.