Can an adult explain please?

My ex and I started casually have sex in 2016 off and on but I never wanted to make it official, my ex did, then we dated in 2021 but broke up in 2023 because of cheating. Despite multiple betrayals by my ex, we got engaged briefly but it didn't work out. Now, despite trying to move on, I still find myself in love with my ex and wanting to be friends. I wonder why I can't let go, even though I've tried. I’ve been emotionally and mentally abused. I’m also guilty of betrayal but not compared to how I was cheated on and betrayed. I was cheated on 20+ times. 😔 I wouldn’t mind being physically abused that’s how attached I am… I’m not sure why and I hate it because we spoke today and it was my idea to be friends. And now I want to drink…