it kills me inside

When someone walks out of your life, let them, even though it hurts you some much to see them smiling and moving on with their life. There's no use in wasting your time on people that leave you, nothing will ever going to be the same as before. What you make of yourself and your future is no longer tied to them, you just have to try to close the door of the past. Yeah, you will miss them for long time and you will always have a special place for them in your heart. But while tears are dropping in the corner of your eye you have to remember that you weren't the one that gave up.