I don't know how you can get over this but I am ever so thankful you are not a part of this person's life anymore - or ought not to be. Can you or have you been able to detach yourself from this person? I suggest the further you get away and the more you involve yourself with others who you have a healthy relationship with the easier it will get.

You are right, the world seems to unfair. But I make the most with what I can.