There could be several reasons why a guy might stop talking to his female friend after she declined his romantic advances:
Emotional Disappointment: The guy might have developed strong romantic feelings for his female friend and felt disappointed or hurt when she didn't reciprocate those feelings. In such cases, he might find it difficult to continue the friendship due to the emotional pain.
Miscommunication or Mixed Signals: Sometimes, people misinterpret friendly gestures as romantic interest, leading to confusion and disappointment when their feelings are not reciprocated. This miscommunication could create tension in the friendship and cause one person to withdraw.
Difficulty Handling Rejection: Rejection can be tough to handle, and some individuals might find it challenging to maintain a platonic friendship with someone they were interested in romantically.
Awkwardness or Uncomfortable Feelings: After expressing his romantic feelings and being rejected, the guy might feel awkward or uncomfortable around his female friend. This could lead him to distance himself to avoid any potential awkwardness in their interactions.
Preserving His Emotions: To protect himself from further emotional investment, the guy might choose to step back from the friendship to avoid getting hurt again if he continues to have feelings for her.
Fear of Being Friend-Zoned: Some individuals might have a fear of being "friend-zoned," which refers to developing strong feelings for a friend who only sees them as a platonic companion. To avoid this situation, the guy might distance himself.
Comparison with Other Romantic Interests: It's possible that the guy might have other romantic interests, and staying close friends with the female friend could make it harder for him to pursue new relationships.
Desire for Space and Healing: In some cases, taking a break from the friendship might be a way for the guy to give himself space and time to heal emotionally.
It's essential to remember that everyone handles emotions differently, and there's no one-size-fits-all explanation for why someone might choose to distance themselves after romantic rejection. If you find yourself in a similar situation, try to communicate openly and honestly with the other person. Clear communication can help both parties understand each other's perspectives and potentially salvage the friendship, even if it requires some time and space to heal.