Wired:
In the Minneapolis area, there was a guy that got dumped by his girlfirend. This guy kept calling her, stalking her. She got a new boyfriend. The guy broke into the house and killed the both of them. (She had a restraining order, what good did that do her?)
Is your guy the jealous type? (sounds to me like he could very well be that type) If he is, then you best both get a restraining order, AND get yourself a gun for self defense. My understanding is that you guys up in Canada cannot own a handgun. Well then get yourself a hunting rifle and keep it within easy reach.
This guy has issues. you say that he is "ok" when he is sober. I disagree. He just happens to be able to control himself better when he is sober, but the feelings of him wanting to kill you are always there, sober or not. He has never demonstrated those "threatening to kill you" statements while he is sober, but they will eventually come out into the open.
My advice would be to get all the protection you can.
When your out away from home:
Get yourself a monster can of pepper spray and keep it in your handbag. Keep your cell phone near.
When you are at home:
1. Get yourself a dog. Does not have to be a big dog, but dogs give you an early warning if someone is approaching your home.
2. Get yourself a rifle and know how to use it.
Cut off contact with this guy completely. Get him out of your house immediately. I would change your phone number, and get a new email address. The less contact the better.
Wired, we do not need another stastic to read about. Don't laugh it off, and get into the "oh it won't happen to me" type of mindset.