Knowing what I know now about living with an addict, my advise would be to run as fast as you can from this relationship or you will undoubtedly wish you had in the future. It gets so much more complicated and hard to leave the longer you are in the relationship and if you later have children together. He is an addict and as such he really can't love anyone else as much as he loves the drugs. If he was only dabbling in it and not addicted yet, he would quit for you if the relationship meant enough. As an addict, he won't get help until he wants help and that probably won't happen as long as he hasn't hit his bottom and become more miserable using than not using.
11 months isn't that long. Knowing now what I know about living with an addict, I wouldn't invest another minute in that relationship. Don't settle, look for someone who is healthy or at least strongly involved in their own recovery.