Is this normal?

I have a habit, possibly unhealthy, of cutting people off--particularly those who have hurt me. The same rules apply to exes.

I normally cut them off and just forget they even exist, lol... But this time is different, and I have no idea why. I recently broke up with my boyfriend, we were great together and even called each other our soul mates, but ended things because of his depression and indifference towards some things going on in his life. Anyway, it hurt to the point where I cried over him... But I don't know why I can't let him go. We're friends now, and this is weird/new to me because I would've cut him off by now...

I'm just confused. I know I should move on but I can't either. What the fuck is happening?