What should I do in my relationship?

Me and my girlfriend have been dating for almost a year now but every time we argue she says the most horrible things to me. She says she’s gonna cheat on me and that she won’t care when she does, calls me names, belittles me, and use everything I’ve ever opened up to her about against me. She makes me feel like trash and treats me like trash when she’s mad. When she gets mad at someone that’s not me or something that happens she uses me as her punching bag and just blames it on me. I don’t know what I should do here anymore. I’m exhausted. Does anyone have any advice ?