Ex boyfriends

So my boyfriend cheated on me , and i never knew for sure if it was true so we had got back together because i'm stupid , then he cheated on me again BUT with my bestfriend . I don't know what to do because i feel lost , like i need him i want to move on but i can't . Like i feel empty , i have him block on everything but when he left he took a piece of me with him , i can't think right like i'm alway quiet now , so what y'all think is wrong and what i should do?