help me someone

I'm with my boyfriend for almost a year now. And first, like, months ago, he cheated on me with his ex. And now, I found out he was texting some other girl yesterday. And also, we had so many arguments, and it's just too much to say, but he's not treating me how I want to. And I texted him a very long message now, and saying how I feel, and please, for him to change. I don't know how he will respond, but I have bpd ,so everything I feel so much, and he doesn't understand this. For him, everything is nothing but for me. Everything is so much, I feel it so much. I wish he could be in my body and just feel how I feel. Even for one day, it's so hard for me to be normal and calm all the time when he's treating me like this. I know in the relationship, only at first, it's so perfect and everything, no arguments, but I want it all the time. He's now treating me like I'm his friend and not girlfriend. He calls me names even for fun, and just no respect sometimes. And at the start, you know, he was all sweet. I want this sweetness back, and I don't want for him to be mean or treat me like a friend. I want him to send those paragraphs and just feel that he cares and he loves me so much. I send him now the message, if he will dismiss this and say something like i’m wrong ,or you know what I mean. I'm gonna broke up, but if he will change, I'm gonna stay. I hope he will change, because I really need him. Like, I have bpd ,so it's really hard for me to leave someone. I'm so attached, I know what to do, and my bpd ,is not even helping me.