This may sound..... harsh..... but if I were you I'd RUN.
No kids? No communal property? RUN.
This comes from 14 years experience dealing with my "issue" (heroin addict sister).
My family and I are stuck with her and I can't ever imagine, knowing what I know, willingly signing up for what she has put us through.
Please get yourself checked for HIV/AIDS and Hepatitis even if he says he wasn't using needles/only clean ones. An addict is first and foremost a liar.
Sorry if I sound like a jerk. Please be as selfish as you can and take this time to work on you. He will need to put all of his effort into recovery and needs the space himself.