Hey pretty blond,
I know 100% how you feel. The situation with my guy was a bit different since it was long distance and we were not in a real relationship, but we liked each other. But so many things you wrote, seem very familiar to me.
His behavior towards me changed, he started to ignore me, everything became weird. I also thought he had someone else. He was not the man anymore that he was when we met. When I was about to go to his country, and we were supposed to meet he tried to end our thing first with weird reasons and when I reached out to talk about it, he told me that he's a recovering addict and has relapsed. In the end, he ended it so he could focus on his recovery. As your A, my guy is very intelligent, very talented and just a wonderful person. I couldn't believe either that this guy was gone due to addiction. Like you I was never exposed to drugs, i don't even smoke. I could go on and on, our situations are very similar. So i know all those feelings you feel right now. I've felt them too.
As the others said it is very likely that he relapsed. I can't really tell you what to do. I think as long he's in active addiction you're better off without him. It's too unstable, too painful and too dangerous. But since i'm still in the same boat as you, i guess i can't say what's the right thing is to do. My advice is read around the threads here. learn about addiction, so you can understand it a bit better. It helped me. Other than that, it's difficult. It sucks very much and it hurts and it's scary. Maybe it helps that it's not your A that's doing this to you. It's the addiction, so try not to take it too personal.
Yeah, as i said i can't give you much of advice, but i wanted to let you know that you're not alone and that i understand what you're going through! I hope that helps a bit! Lots of hugs for you!