Whenever I hook up with a girl, even if it's just a one night stand, I find myself getting very jealous. I think about other guys that she has been with or will be with and it fills me with a very negative jealous emotion. I know that it's wrong and unfair, and it sure as shit doesn't feel good, but I'm quite lost at ways to get rid of that feeling. Any suggestions on how to move forward from this juvenile mindset?