Help? My Friend Has A Horrible BF. . . .?

Mmk So Theres This Boy , Hes A TOTAL man slut . Like hes only 14 , & hes had 3 times , made out , done other things , and has gotten introuble by police before , and then he liked me but i didnt wana date him casue what hes done and because my friend brooke liked him , and then my other friend lexi was telling me to date him and matt kept telling lexi stuff like im in love with her and i need her id do anything for her and he was like carving my name into his arm ( cutting himself) THEN i told lexi that its important to me that girls shouldent date their friends crushes and i liked him but brooke liked him so i didnt date him . then i told lexi if he still liked me in 2 weeks , i will concider it cause he is a man slut and i thought it was just a fase . then lexi dates him ! I was like , THE FAAAAHHHK?! Then , like they have been dating for a month and like 3 weeks and they had some fights but nothing big , tthen he calls me for advice casue he hes in 9th and lexi is 8th grade and all they do is kiss on the cheek cause of her reasons idk and hes like its not going anywhere i think ima dump him annd he told me how he likes a girl named riya. then lexi cam over and she was like 'SO, i went to matts house and his mom said that robert said something that made him upset and he was talking with selena on the phone for a long time (im selena)' then she gave me that look like explain , so i got guilty and told her then she left and cried and we talked on the phone and now shes still dating him cause shes all 'ilove him ill do anything to stay with him' . i mean , im her freidn and all but sometimes i wanna explaod and tell her all this and be like , ur so dumb to still date him after all this! cause like basicaly he was ganna dump her cause they dont kiss or anything . and now he hates me cause i wasnt supposed to tell but i did . i mean my boyfriend (EX i should say) cheated on me and i got so mad like that my friends kept it a secret and it wouldd have hurt less if they told me right away . now im like so insecure about my looks cause i mean the girl he cheated on me with is WAY prettier ., and me and him only went out for 3 days then he cheated on my . Ugh boys xD but yea . So whats ur opinion on all this?