Depends on the nature of person.

  • Some people realize their mistakes.
  • Some people take it on their ego and want their pet back.
  • Some just want to keep you as a back up option.
  • Girls usually do it for two reasons.
    • Back Up option
    • Love relapse
    • Ego is not always an issue with girls.

In any case make her double the work to get you again.

https://hemantpandeyblog.com/2017/12/31/how-do-i-stop-blaming-my-defects-and-inadequacies-for-which-my-girlfriend-rejected-me/