<human>: Condense the text into a few key points

I dated this girl for about 4 years and I cannot seem to get over her. I guess I'm getting better with handling it I don't think about it much anymore but it seems no matter what I do to help myself I can't get her out of my head. She's constantly trying to add/follow my new SO and her friends on social media networks. I have her blocked on all of my pages and don't know what else to do.

 She was my HS sweet heart and within the last few months of the relationship cheated on 4 different times by going all the way with 4 other guys. She broke the news to me by saying she wanted to tell me before her best friend at the time (who had known aswell) did. 

I know I shouldn't go back. I haven't considered it. I just want her out of my head and for her to back off of my personal life. How should I go about handling things?

I should add we had a great relationship I believe it was love. She said she was drunk the times she cheated and mad at me one of the times. (still dont understand how one could be THAT mad). It all had happened within the last few months of the relationship. When she had started hanging around this new best friend, who I told her that her best friend was going to cost her our relationship.

For more info just ask. Sorry about shitty formatting. First-time poster here.
<bot>: Long term HS sweet heart cheats and is a mild "psycho-ex" girlfriend. Need help getting her to stop and getting over her.