omg please help

My ex likes me again.., My boyfriend and I want to keep the relationship private, like keep it our business but my ex found out because my brother is friends with my ex and he told him after my ex told my brother that he wants to get back with me. My brother and I are 2 years apart and I did date my brother's friend (which is my ex) so they're not gonna stop being friends, so he does come to my house and he does talk to me. My boyfriend knows about it, but we always made sure my plans never aligned with my brothers but since my brother told him he comes when my ex comes and it gets pretty heated, since my boyfriend now knows my ex likes me. And my ex is a real dick about it too, his jealous ass is crazy. He says things like "don't you think he's too clingy?" and I say "no, I think it's a perfect amount" and then he said "bro chillax, you're gonna squish the poor girl with your hugging, ion want her at least I had her before you" (there was a lot of conflict before when he knew that my boyfriend wanted to get with me, but shit happened and then my ex and I got together but when we broke up, he didn't know my boyfriend and I got together) then my boyfriend said "she's fine. She likes when I give her hugs, and you may have had her first, but you guys didn't even last longer than 2 weeks" and then my ex said "you're talking shit about her" and my boyfriend said "nah she broke up with you, plus your the shortest relationship she's ever had" and then my ex said "you're definitely not her longest either" and then I interrupted said "yes he his, I've been dating him for 2 years now" and my ex is SHOCKED. And then my ex looks at my brother and said "wtf" and then my brother said "well you never really asked if she was dating, I wasn't gonna bring that up, plus she told me after it was her 1 year anniversary." and my ex said "so who's confirming it's been 2 years" and I said "you can see the pics or you can ask our parents" and he just stood there shocked. And then he said "no way you're dating this fool, what's so good about him" and I said "could you not call him a fool?? Everything is good about him, something you clearly never had in you" and he said "then why did you date me" and I said "for fun, duh what else, you think I actually liked you??" and ofc I lied, I didn't want to say I liked him at all. And then he said "wow so your a cheater" and I said "wow you manipulated me, and hung out with several girls and told my best friend if you guys could get together and said all that was a joke...!?!??...and I'm not a cheater, I broke up with you and got with my boyfriend a month later so you chillax" and he said "I never did that" and I said "if you want the proof I can show it to you" and he goes "bullshit, imma play basketball with your brother, you pussy" and my brother didn't wanna involve himself so my boyfriend stepped in and said "call her a pussy, I'll break your stupid ass face" and my boyfriend legit could, my ex does work out but he's not as strong as my boyfriend, and plus my boyfriend is a year older than my ex. And I stopped all this and said "hey babe, lets go get some food" and then my boyfriend grabbed my hand and we left and I saw my ex look at our hands and scoff. LIKE BITCH WHAT. And this shit won't stop it's getting worse and my ex is being a dick that my boyfriend said that if he annoyed any of us, he'd knock his teeth to the back of his throat. My boyfriend is protective and makes sure that I'm okay, we've been friends for ages, and he gives me princess treatment, and I like that he makes sure I'm okay, and will stand up for me and even be protective about things and I like knowing that he wants me safe and wants me for him only, and I like the fact that he'd choose me to be with him all the time. He has no friends that are girls, because he wants no problems, and he makes sure that I don't have to be like that, like he'll let me have guy friends, but he just wants me for him, and I'll always love that, but my ex is getting him mad, and I've never seen my boyfriends mad, like ever. And I think he's serious about punching my ex because he's saying shit things about me, and my boyfriend is not gonna let it all slide. So what do I do to prevent all of this??