I am excited for you. Yes, it is no doubt scary and unsettling to be starting such a new and different path. But maybe you can find a way to embrace it. It is NEW and DIFFERENT. Go back and read your post. You are much happier when he's not around.
Think of the things you can do when you are happy so much of the time. Think of how much more energy you will have not encumbered with him.
And you can always think about a future with him in it. You leaving may be the catalyst for him to reverse his ways and return to who he was. It "could" happen. Just don't bank on it.