Your post reminds me so much of where I was. Like so many have said, I kicked out my ex so many times after the relapses and always went back just to find more lies, deceipt and drugs. Finally, almost a month ago, I took that break and am sticking to it. I had no contact with my ex (until yesterday!!!) for almost a month. I never thought I could do that. The last round involved me telling his parents (again) that I found pills and they sent him to rehab. I received a call from his work number which I didn't answer yesterday from him telling me he wanted to send some money he owed me. He needed my address which I thought was incredibly strange given he had been to my house a million times and could easily find my address online. Anyway, there were texts saying how incredibly sorry he was, that he still loves me and that he's in daily meetings and finally has a sponsor.
My point is that for the first time I can finally feel that I'm NOT going to break down and go back to him. If I hadn't detached and told myself I need to take care of ME for a change and stop worrying about what he's doing with his life, I would still be on the roller coaster ride and destroying myself in the process.
Do I still care about him? Absolutely. Did my heart sink when I heard from him? Absolutely. Do I want him to get better? Absolutely but not more than I care about me getting better. I head to reach that point after so much turmoil that I brought on myslef from continuing to go back break up after break up after break up. If I would have just listened to my instincts and my family and friends a year ago, I would have saved myself alot of grief.
I'm so sorry you are going through this and we all can relate. I'm glad I found this forum. It's helped me to stay strong and realize I'm not the only one going through all of this. I hope it helps you as well.