Is this the first time you've ever held firm to not having contact with him?
Typically, the addict will try to reel you back in with new promises, etc.
Read some other posts and you'll see this is true and not really unique.
Actions are what counts.
If he means it, he will get sober and work a program on his own and respect your distance--other than that, I wouldn't take this as anything else than not respecting your boundary.
Sorry to be a downer, but I'm on both sides of the fence and as a former addict,
I would promise the moon to get the status quo back.
Until I was ready to back my words with real action in working a program and maintaining sobriety over time, it meant absolutely nothing.
Sounds like he's doing the same.