I know you already know these things logically but:
You don't have to answer the phone to him.
You don't have to let him into your home.
You can call the police if he becomes aggressive or you feel threatened in any way.
You do not deserve to be treated like this.
You are not responsible for his shitty behaviour.
You are not responsible for keeping him calm or making him happy.
You have the right to be treated with love and respect.
You can ask for help from Women's Aid.
You are not pathetic. There are thousands of women who work in high powered jobs who can't escape from abusive relationships. The fact that you are being abused is not a reflection of your worth.
If he begs and pleads for you not to finish the relationship, remember that he won't change. He has shown you who he is. Now believe him and walk away.
You really need to end this relationship. If you believe that doing so will put you at rick of harm, contact the police/Women's Aid first.
Keep repeating "I deserve better."