My Ex Threatened Me

I have a friend that I used to date that basically cheated on me. We weren't friends for a while but we are now. He is doing what he calls "trying to get me back" but he keeps saying rude and mean things and I hate it. So Monday he was on the bullshit and made me super mad so I stopped talking to him again. Friday I talked to him because he kept blowing up my phone and we had an argument because he was mad cuz I haven't been talking to him. So through the 3 hr argument he got on that crazy shit, threatening me, then said he would kill me and I was like wtf and he said "when the police ask me why I did it Imma say because I said that if I can't have her no one can". That pissed me off and kinda scared Me so I told him I was gonna hang up and he was like no I'm not cuz if I do he gonna do something to me. Eventually I hung up and he texted me "Bet" and I was like bet what. He never answered. Saturday morning he text me GoodMorning and I didn't respond then a few hours he texted me saying that I could've responded and I said yeah I could have but I didn't and he got mad and was like fine you don't have to talk to me do what make u happy blah blah blah. So I didn't text him bck. A few hours after that he texted me saying he wish that I would talk to him then a hour or two after that he said "baby I'm sorry talk to me 😶" and I'm like dafuq. You know I'm taken and you callin me baby? But I didn't say that to him I just ignored the message. Idk what to do, I've had this type crazy issues with a guy. As a first step I told my boyfriend what happened and he asked could he beat him and said no. He said fine but if he put his hands on me then he gone hurt him and I said okay. I don't wanna tell the school because Imma have a PT and my mom already don't like the school or me and she already looking for a reason to homeschool me or transfer me and I can't have that happen because I'm actually happy with a school for the first time ever. He is still blowing me up right now. Today is Sunday and he is still blowing me up. What else should I do?