I'm a girl, so i'm not sure how i feel about this.

I picked up my boyfriend's sisters laptop and i saw this message on discord with my boyfriend telling my boyfriend's sister that, she's 15, he's 17, to "shut the fuck up before you end up like your brother or your mum". I replied to him asking him about the message and he gave me a bunch of BS and i told him i wanted space and that i would talk to him about it in person and i told him that he was a disrespectful piece of trash with "no regard for the woman in his life" and he said i was a "bitch" and then he just kept saying "i'm sorry" and i told him that "sorry" doesn't help anything because he's a piece of shit and i just wanted to avoid him and the topic entirely. I told him he needed to grow up and that he needed to give me space and just leave me alone but he just told me "I don't give a fuck about space I don't give a fuck about apologies I just need you" and he started saying that he loved me and he "would die for me" and i felt like a total idiot for thinking that he actually cared about me. I feel super dirty and he's been saying he "would do anything for me" and he just keeps profusely apologizing and getting angry when i tell him that i'm uncomfortable. what the fuck is wrong with this guy? and what do i do?