JMOHO I think he wants to control you plain and simple. You did not mention if he is angry at you for something you did to him in the past so I'm assuming he does not have a gridge on you.

If he does not have a grude on you, I think it is safe to say he is an evil man that wants to see you quit because that is an ego booster for him and his friends.

That being said it is a very sad world we live in and so many people are very demented by the notion it's okay to kill people emotionally just as long as you do not harm them physically.

I really hope you are able to keep your job. If you feel you must quit, I wish you the best of luck in the future!