A BROAD question.

There have been times in my life when I could drop it, spin the tires, be out of sight and never look back.

Then there are times when I've had to give up and move on when I didn't want to.

Then there have been times when I knew my life without that person would not be the same and I find it incredibly hard to move on.

Depends on the person, the situation, the timing, the environment, the stage you're at in your life. Many factors not just one.