Repeat after me.
"I need space. Please leave me alone."
"If you're still sober and I'm still single in 5 years, then we'll talk."
"I need space. Please leave me alone."
Over and over and over. No matter how much you want to talk to him. Eventually you'll start to believe it yourself. That's how I did it, and it was really freaking hard. But it worked, he got it, and he quit calling.
Agree with Suki. He knows how you feel, and you don't have to keep reminding him. Just be a broken record.
No contact helps a lot.