idk why i'm so obsessive over him. i know he's bad for me

our relationship was toxic. he lied, cheated, stole from me, used me for my car and my money, and treated me like shit. after 2 years, he cheated on me again and i finally broke up with him. 6 months later, he's back in my life and he says he misses me and he can't stop thinking about me and he wants to be friends. i gave him another chance and he lied again and used me again. so i dumped him again and blocked him on everything.<br><br>sometimes i get this sinking feeling in my stomach where i miss him, and all the bad things he did to me don't matter anymore, i just miss him so much. i've been in this mood for about a week now. i look at his pictures, i look at pictures of us, i'm listening to music we used to listen to together. i think about texting him, i think about calling him. i don't know why i'm feeling this way, i don't want to feel this way. he was so shitty to me and he did so many things that hurt me. i don't want to be in a relationship with him again, but i seriously just miss him.<br><br>i feel like i'm going crazy. i know he's not good for me and i don't want him in my life, so why do i miss him so much? why is it so hard to get over someone who treated me like garbage?