relationship emergency.. what do i do ?

so… my boyfriend(M21) of 4 yrs and i(F20) that i live with, have had a very rocky and sometimes toxic/relationship where we should of ended multiple times in the past 4 years. our relationship is where the love is strong but there’s no respect for my boundaries or in general, no commitment from his end and no effort from his end. and he always makes promises to work on himself and stop hurting me, but then he just stops after a month and repeats for another month and then when he gets close to losing me he says he’ll try for real this time. and i say okay we’ll try again. but it always goes back down and the cycle repeats and i let it because he’s a narcissist, a love bomber and manipulative. and when the cycle repeats over and over after you begin to build resentment for that person because they break your trust and hurt you over and over. and then you begin to detach. but I CANT. bc i can’t keep doing this to myself, i can’t do this all by myself, healthy relationships aren’t like this & healthy men aren’t like this. so i need to start putting myself first bc he’s already been only putting himself first. bc if i don’t then it’ll just tear me down more and more & i don’t deserve that, i’ve had a really hard life all this way & i shouldn’t feel this way anymore & i can’t keep forcing myself to stay here in hope for stability but never is any. i don’t deserve that, & i can’t keep falling into these traps, and i hate saying that they’re traps bc i KNOW he genuinely LOVES me, but i know he doesn’t treat me how someone who loves them tremendously treats the other person. and so that’s why they’re traps. & dear god do i love this man but it’s also a trauma bond that we have bc we’ve been through so much when we were just kids. but before this most recent last chance i’ve given him… our sex life begin to lesson and the desire and intimacy hasn’t been there in a while(bc we live w his parents) and we haven’t had sex in 1 1/2 months maybe two.. and it’s because i just no longer felt desire or WANT for anything sexual stuff.. and i dont know why, i feel like maybe it’s from the resentment.. but so this most recent last chance i’m giving it rn.. we had sex the other day and we’ve always had INCREDIBLE sex, and so i enjoyed it. but before that and after that i just wasn’t sure cause like i said i haven’t had the want for anything sexual… and the sex we had recently felt good but i only felt desire for the feeling and i’m not sure if i had desire for him. and i dont know why i haven’t had desire for him in the past couple months that our relationship has went down again. and i’m not sure what to do ? have i lost desire for him? am i not attracted to him? do i fix that or let things end? what do i do? :(