This thread makes upsetting reading. I don't think you are an abuser OP. But I do think you are being set up to be the bad guy. This thread is a taste of the way you are being set up. If you continue down this path it's a taste of what you will get.
Please please save yourself. You ARE worth it (sorry sound like a hair advert, but it's true!).
You need to save yourself from this bad situation. He will end up destroying you.
Think about it, your attempts to reach out to him are being twisted and turned into 'assault'. He is doing this to make sure he hurts you and punish you. It's disgusting. And it's not something a good man would ever do. Please stop reaching out, and start to think about yourself in all this. If you're too busy sacrificing yourself and getting swept up in his manipulative needs, who looks after you? You're both fixated on him, and the dynamic is, whatever you do is wrong, whatever he does is right. And that's not ever going to end happily.
Please don't get pushed into being the bad one, listen to what he's saying.what he's doing and saying is 'I'm a manipulative weak coward and I want her to go or I'll break her'.
He sounds pretty dangerous to me. Don't get tricked into feeling sorry for him or wanting to save him from mental health problems. Two joints a day is never mild use. He's an addict who can't control his habit. He's not someone you can ever trust as his emotions and self are being mediated through his drug habit. I know people with this kind of habit - an ex of my friend. They expect their partner to play second fiddle to his smoking habit. And lash out if anything comes between satisfying his addiction. I met him after they'd split up, he was very clear she was the horrible one who'd ruined his life. Then he started to roll up in front of my baby. I said no please don't smoke in front of my baby, especially not a joint. He got very angry, told me I was a bad mother for not letting him light up in my own house a joint which would leave me feeling stoned by second hand smoke, let alone a tiny baby. I realised then what a selfish addicted she'll of a person he was.
It's not you, it's him. But it will be you if you carry on supporting his psychotic habit and settle down to be his emotional punching bag - which sounds close to being his physical one as well.
Good men don't behave like this. Please walk away, restart your life and start to love and care for yourself. There will be other relationship, and if you are treating yourself right, it will help you create friendships and connections, even if you are an introvert.
But if you stay with this awful man, your own mental health will suffer (is already suffering), and you'll find it harder and harder to leave.
Good luck OP.