The insecurity is understandable, but given that this is more of a fling than a R, try to step back and separate your emotions from it if you can.
Now, on to the other stuff. Please get tested ASAP. Heroin users are notorious for sharing needles. Pot smokers are tolerable IMO, but the hard stuff usually means much deeper problems and lapses in judgement.
You said it yourself, this is a fling, he doesn't want a R and, honestly, would you want one with him? He sounds childish and flakey and we all know that you are NOT either of those things. Your smart, beautiful, creative and witty. You deserve an equal in those areas and I don't see him being it. A fling is fun, but this sounds like it's starting to hurt you. End it before you get sucked in too much further.
Love you girl!!!!
T19 M15 S19 XH47 M43 bomb12/4/07 PA5/07 S12/26/07 D final 11/17/08 Back together with no defined R 05/2010 confused....to say the least!!!