Not even sure what to do anymore... any advice?

alright well i was with this guy for a while and all he did was cheat on me but then he got serious with things and he wasn't playing around he seemed like he really wanted to be with me. But i didn't think he was for real and i broke up with him because i was sick of his crap. And i ain't gonna lie i love him alot and i really wana be with him. well time went on and we ended up back together. and im not even gonna lie i really like this foo. but i went away for spring break and he got a hickey from some other girl and he told me about it so i forgave him. but when i got back i couldnt see him for a while and the day before i was able to see him my so called best friend comes over and she had 3 big hickeys on her neck. i asked her who they were from and she didnt want to tell me but she did and it turns out they were from him. so i broke up with him again and now i guess he tryin to get wit her but she doesnt want to be with him or atleast thats what shes telling me. But im like in tears right now and i dont know what to do i mean i love him so much and its hard to let go. i dont know how to let go!! any advice. what should i do? how should i feel?... dam