1. Emotional Memory: Boys may keep their ex girlfriend's contact information as a symbol of an important emotional memory, unwilling to completely let go of the beautiful or painful experiences of the past.
2. Potential Connection: Boys may believe that there is still a possibility of maintaining contact with their ex girlfriend in the future, whether as friends or in other forms of interaction, so they choose not to delete it to preserve this potential communication channel.
3. Laziness or Negligence: Sometimes, boys fail to proactively delete their ex girlfriend's contact information simply because of laziness, busyness, or negligence, without realizing the importance or necessity of this behavior.