How to detach yourself from toxic people

How do you guys deal with dropping a toxic friend? If that friend was more or less you’re only friend.. for so long this person has been a person who told me if I hung out with people without her to not hit her up. Fought with me if I made plans and didn’t make it so she could go ( even if I didn’t make the plans I was invited and thought to invite her ) I was always always always the butt of her jokes for entertainment. I feel like even tho I know this person is bad for me I feel this strange feeling of wanting to apologize and wanting their validation or approval. How do I unwind myself from wanting this person in my life? We’ve been friends almost 10 years