Narcissist Relationship

This morning I broke up with my bf of 4 years. We have a child together. This man has cheated on me and beat me... you name it. He’s very verbally and physically abusive. What I am wondering is... how the hell do I make my brain snap out of to see I don’t need this man? It sounds like a no brainer I know. But I just don’t know how to cope with it even know I want him out of my life. He’s like a snake and always finds his way back into my life.