I see no reason to stay.
What are you so scared of?
Being alone? The unfamiliar? Change?
Make a clean break I say.
Just because you've made a mistake doesn't mean you automatically have to continue making it... You have the option of rectifying it.
And he IS a mistake, no doubt, he has all the hallmarks of an abuser and you deserve so so so much better. Yes, sometimes better is downright scary, I was scared shytless myself, but I did it anyway, and you can too.
Walk away, open the door to a healthier happier you.
Don't allow fear to cripple and trap you any longer.
If you're still in doubt.
Draw up a very honest pros and cons list of your relationship.
You'll soon see how clear the answer is, and then you can plan your exit strategy.