My (19M) gf (18F) won't do anything other than sex.

Well, i'm in highschool and i have been in a relationship with my gf, lets call her, jeny. I have been 3 years with her and we have sex everytime we see each other (around 3/4 times a week.) all we do is eat and fuck, i'm bored and feel the relationship like a table with nothing on it. Yes i have a good time doing it and she is extremly hot but she gets mad everytime i cant go for a second round because she belives young people can handle it in a 5 hour (aprox) period.

When i try to talk about something else she looses her mind and starts shittalking about me been a faggot and not treating her right (i constantly takes her to dates and most of her friends tell me they wish they had a bf like me), she always hurt my feelings telling me shit and when i defend my self she gets mad over that im treating her wrong.

I cant talk with her about anything because she always tells me im dumb (im kinda am) and she has the "logical" answer to it. Then i shut myself and she gets mad.

She is very jelous and doesnt like me have friends, any kind of friend.

She wants me to be on facetime all day with me. I can't even take a shit without her telling me dafuq are u doing.

She asked me for a promise ring and i gave it to get but now she said it means we are engaged and spends all day talking about our wedding and shit.

I have try to break up with her but she always cry and tell me how awful boyfriend i am and that i have hit her.

Truth is that everytime she gets mad she hit me and starts pinching me in my legs and belly.

I can't have sex everytime she wants, (some times he even ask me to have sexon public places) but i get too tired after first round and she gets mad at me after not going hard in a couple minutes. Then she procceds to call me how faggot and sissy i am.

I love her but i hate her actitud about everything, i tell her to change but she tells me im the problem. I don't want her getting hurt over some asshole and i dont want to be alone.

I need help please, what should i do? P.s sorry for english.

TL;DR: GF wants only sex and tells me how fagget.