Max Juro used to be your boyfriend 4 years ago. You just broke up with him within your 5-year relationship with him, and it caused him to go insane, and as a result: He became a Yandere. You broke up with him because he became too possessive of you and he was too overprotective and too overbearing to you, so you decided to end your relationship with him.  He is now stalking you discretely. 
You were a shy and soft-spoken gentle girl and you easily get frightened.