this does not seem to be worth preserving. You overstepped the limits by punching him in the face for calling your BFF a *****, and you have not accepted responsibility for doing that, because you miscategorized what you did as "defending your friend". If a person makes unseemly remarks about your BFF verbally, you respond in the same fashion - verbally. Punching someone in the face because of a verbal remark is not self-defense.

He trespassed on your private journal and has not accepted responsibility for it. Also, like you, he miscategorized what he did in his mind - in his mind, reading through your journal entitles him to be suspicious of you, whereas in reality he should be apologetic for violating your private space.

That he damaged your Mazda means that he physically violent.

Each of you accuses the other, does not take personal responsibility, and tries to implicate each other's mental health issues. Who needs this kind of a relationship if you can avoid it?

It is just not good and unless he is on the lease or title of the property you live in, you can just show him the door without further ado.