I HATE MY BESTFRIEND:( (but i need your)

Have you ever had a bestfriend who really just dont give a fuck??? a bestfriend who sit here everyday and keeps on making the same mistakes ova and ova again yo...i have this bestfriend(shelby)who i would try and gve the world to i buy her erethang shoes clothes anything i think about her before maself thats how big of a heart i have i was working she wasnt i was basically giving her a allowance out of ma check lol ik im dumb but i mean i would seriously drop everything when she's sad or down and go to her crib to be there for her even when i have to walk for miles i member when ma bestfriend whom i havent seen in 2 years had came to visit and shelby was home crying because of ma dumbass cousin had called me i member i left ma bestfriend to go ova there knowing she was only here for a couple days and i wouldnt see her for a while i stll left and a couple days later shelby fucked me ova she left me downtown when i was having a bad and i was balling she left me for a bag of weed and ma cousin...i forgave her for that to... and she keeps fucking me ova i mean i went against ma family for this gurl yo my own ma kinda hates me for it, ma friend yea she can be bad newsss she's been recently in and out of lock up and everybody but me turned thier backs on her, she started dating ma cousin a year ago who's really bad news and i hated it yo because its gross he's was 20 and she was 15 when they started now she's 16 and there's something really wrong with him yo and i fought him one day because he called her a bussdown which is a hoe and we got into this physical fight and i beat his ass in a gym where everybody was and the next day or so this bitch goes back to him, now i looked stupid for fighting ma cousin for this bitch yo but i forgave her for that but this time the court made it clear for her not to see him or she be sent away she's on her third strike and i'm decieding to walk away....what do u think should i walk away and say fuck ma bestfriend move on??? but u have to realize this gurl is ma bestfriend to and she would do anything for me to if she could yo seriously she's was all i had.. should i stay cause its obvious she's finna get fucked ova again and will have nobody to turn to??? but if i leave her it wont be like im bestfriendless because i still have this one good ass friend who comes into play throughout all these bullshit ass experiences wit da bestfriend shelby but i will tell u more about that good ass friend later...but think about ma questions and if you could leave a response in a comment it would be really useful...but im out yo duces...