How Do I Leave a Toxic Situation?

So long story short, I lost my virginity to a guy who I was really close(friends for 2 years) to my senior year of high school(currently entering my sophomore year of college) when he was heading into his freshman year of college. We were good friends but he was never my official bf, but I had alot of feelings for him which transcended into love after he took my virginity. He initially led me on with the idea that sex would "bring us closer". However, with him being in college at this time and me still in high school, he made it clear we would not be together and the love feeling was not mutual. I was heartbroken but became even more crushed when I discovered two weeks after he had started dating some girl from his college after he told me he "didn't want a gf right now". I cut communication with him for 8 months until I allowed him to weasel his way back with meaningless apologies and empty promises. This cycle of on again off again hookups and breakups has been going on for the past year and has been filled with lots of uncertainty and me feeling like I have to constantly compete with the next girl. Now I'm emotionally drained and I've tried excessively hard to make him see me as the girl he should be with. However, this never works and our "make up" periods never last long enough to actually fix or build anything. I will never understand why he begs for me back just to ruin things again and further hurt and frustrate me. I'm just wondering how do I get over him and heal from all of this because at the end of the day I still love him. However, I'm aware he treats me poorly, ignores me and I'm pretty sure has sex with other girls behind my back. I know it's time to move on, but I'm struggling to break this habit of running back to him.