Rule #1. Abusive people do not change.
Forget the calls here for going through therapy, trying meds, and all of that BS. I've been through this so please consider my advice.
Before the break-up, covertly go out and find a new place to live. It's best if it has some type of security, like an apartment with a secure entry and garage. If you have the means, find a secure neighborhood (guard gates, patrols).
Important: Sign a lease. You won't back out.
The day that you plan to leave for good, wait until he goes off to work, or at least someplace he will be away for enough time to get your stuff and get out. To accomplish this successfully do the following:
Have a moving truck already hired and down the street waiting.
Arrange for trusted friends and/or family to help you quickly get your belongings into the truck.
Once you've got your stuff out, you just leave. Walk out the door and don't look back. He will know you are gone when he walks through the door and realizes your stuff is no longer there.
Don't tell him where you have moved if you believe he could be dangerous.
Give him time to calm down and assess what went down. He needs some time to think over what he did to get you to the point of leaving.
If he's not a total moron and crazed narcissist he may figure it out without your having to tell him, but don't count on this.
Do NOT get back together with him. If he wants to discuss anything and you are in agreement, bring a friend with you and meet in a very public place. He will beg you to come back. He will promise you the moon. Don't believe any of it. Do not get back together with him, hold your ground.
Understand why the relationship went sour. Don't hook up with the same type of person again. Make a vow to change whatever it is that drew you to want to be with that type of personality and fix yourself. You're most likely a nice person that repeatedly gets used by others. That was me. Not anymore.