How to get out of a relationship

Does anyone have any experience in getting out of a relationship? I’ve been on and off with my bd for 5 years and I am TIRED. like really tired. I’ve left multiple times and he still doesn’t get that I am just not happy. There’s no one else involved, I plan on being single and celibate. We have two kids which is why it’s so difficult for me to leave. Sometimes I regret having them because I don’t want to be with their dad. I recently moved back in and noticed I’m extremely depressed and stressed out. I had my own place but it was more of a program and it was a very far commmute picking the kids up every day because we don’t have a custody agreement. I’m so tired my mental health is literally drained. I’ve stopped working because I’m so depressed and I just feel like everything is falling apart. I really hate myself I suck. I don’t think I was meant to be a mom it’s really just hard on me. I don’t have my own place yet so Idk what I’m gonna do. Im wondering if I can even do it anymore maybe I should just give up and start living in my car again. Im having a hard time.