Consider that you grew up with addiction in your life and now you are trying get an addict to change so you can have a fulfilling relationship with him. It's what you know. It's what your comfortable with. It's just what people do when they grow up surrounded by addiction.
Unfortunately it isn't going to work.
And addict has to want change because he/she hates using more than they hate being sober. They have to really want it because quitting and staying quit is hard work. He's already told you he's not ready. So no amount of "sticking around and supporting him" is going to get him to that point. It'll just feed into his addiction by convincing him that he's still got you waiting around so his situation is not that bad, yet AND you'll go crazy in the process.
I'm so glad you found this website. I hope you'll stick around and read all you can. I hope you'll take a good look at yourself and learn all you can about codependency and dysfunction in a relationship so that in the future, you can find true love without having the chaos of addiction attached to it.
AND I hope you'll change your phone number if he continues to call you. So you don't waste the next 5-10 year waiting for him to change. :-)
Oh one more thing. How can you tell an addict is lying? His lips are moving.
And
You didn't cause it.
You can't control it.
You can't cure it.