Advice please

Let me tell you the whole story of our friendship first because it’ll probably make more sense to , ok I’m paris and I joined secondary school In 2015, there was this boy in my form room that I just clicked with but he didn’t love me back , I was year 7 at this point. I spend the whole summer looking for his social media and I’d cry myself to sleep and everything . In year 8 this boy turned into a bit of a dick, he would call me fat and ugly everyday and laughed at me when a girl punched me in the stomach , that night I thought if I messaged him telling him how I felt it’d be ok, but he screenshotted the paragraph and sent it to everyone In my year in my school and I would get THE PISS taken out of me. I litro had no friends bc of this boy. Towards the end of year 8 we got close again and forgave him for all the mistakes he had done and yeah got really close. Ok so we are now at the start of year 9 and he asks me out on 13th December 2017 and I say yes obviously, he was my first kiss, hug everything and I loves him so much , but you know when you see in relationships that one person loves the other person more... well I was the stupid one that loved him more and idk I just felt like a twat for saying yes but 3 years of crying wasn’t to be wasted on breaking up with him. Ok in the May of 2018 I found out he kissed another girl and he didn’t tell me , he let me find out myself so I was heartbroken and I didn’t know if it was classed as cheating or not but anyway about 1 month later he done it again with someone called eve , they would send nudes to each other and I still don’t know if that’s cheating to this day either then that same week he sent nudes to someone called Kaitlin. At this point I met him , I was crying , I told him I wanted to die and hurt myself so much and asked why he didn’t love me. He started crying and he cried all night, to his mum, dad and I felt so bad and he hasn’t done it again since, I can tell he’s changed and he’s so I love with me now it’s crazy like he’s really clingy. I still cry that he done that to me but he makes me feel better yet I think our positions have swapped , he loves me more... I just don’t feel like I did back them and I think of him of my best friend still but I adore him and love him still. What’s your advice (I know “once a cheat always a cheat”)☁️🥰🤔