Getting over an ex

There is this girl that i used to kula back in the day while in campus, but because of one issue or another we had to split ways. We both moved on. Sasa sijui ni kwanini i have been getting this weird nightmares about her n find myself obsessing alot over smashing her again. I know this could open a deadly can of worms....but hey, its what it is. Pray, tell me ye gentlemen and ladies of great wisdom...what do i do to get her outta my system?
Long story short. It happened to me on one chick. I'm not superstitious but I think ni "kamúti" every minute unamfikiria yani every day ningepitia kwake. Even after finding out she was a lanye I still continued with the "relationship" . I deleted her no. and now I'm only faithful to my wife. Never f*** around SOUL TIES itkushika uchizi