I'm so confused on what I should do.

so last year I met this guy. I thought he was sweet and caring and everything I could ever ask for. I gave him my innocence and then he used me for everything and treated me like shit. From money to sex. I dated him for a year, I started doing things I never thought about doing because of him(read my poems). All of that started when I met him. Anyway I finally took the advice from my friends and dumped him. And as soon as I do, my best friend is all over him and he is all over her. Now this girl had told me for a WHOLE YEAR that she hated him and didn't trust him, but as SOON as I dump him shes all over him. So they started dating and I said that I wanted nothing to do with either of them. But after not even TWO WEEKS they break up and try to be my friends again. I told the girl hell no cuz she choose a guy shes known for a year over her best friend since first grade. But the boy... I dont know... he always listened and had good advice, but i dont know if i should be hhis friend again... maybe just texting not face to face... i dont know... i have started dating another guy that I am completely in love with adn he knows everything that goes between me and my ex. my boyfriend said its ok to be friends with my ex. But im still not sure because being friend didn't work before... but i miss having him around. Anybody have any advice for me?