Thank you all! I wish I could say I did it, but (as you probably know and experienced) is not that easy. Today I had a long conversation on phone with him, talked about my feelings (anxiety, etc), I just couldn't do the actual break-up (we're seeing each other soon anyways, it'll be even harder in person, but I feel like I need that), but I said most of the things I wanted (that I don't want to be planning future, that I need time apart, that I feel like I'm too invested in his recovery). His response was suprisingly good, we set some boundaries (not planning future, texting less, etc) until we see each other, and then we'll talk more. I know it's not perfect, it would be best to end everything as soon as possible, but I'll be seeing him after the couple of weeks anyways (tickets are bought, he has plans to visit friends in my city and he's staying in my place, so meeting is unavoidable) and I thunk it would be hard for me not to "get back" with him, so for now I'm trying distancing myself a bit, and then make it the last meeting, say that it's healthiest for both of us if he goes through his recovery alone.