jealousy, kills?

hey yall, I'm posting on here due to the fact that I, may be, a little, crazy?

so i am AN EXTREMELY jealous girlfriend... which i absolutely hate. i would love for it to stop, but i can't?

i try and try, but i just can't shake my jealousy.

so im asking for some advice?

my boyfriend of 9 months has been nothing but utterly commited, sweet, caring, and oh so trusting.

but for some reason when he brings up an ex, or when an ex comments on one of his photos of us, i get livid, so angry and its affecting me.

Like, i dont want to go to places where hes been with her, i get mad if he tells me what he did, once upon a time with an ex, which may i say, he didnt even know me when he was dating her. ive never even met the bitch, but i fucking hate her.

its destroying me, and our relationship, how to get over jealousy?