This is the first time I read your thread. I totally understand your desire to stop the role of caretaker. I felt that way with my drug addict ex. He pulled the same crap on me "Don't you love me? What about in sickness and in health? I can't get better without you..." Blah blah blah blah blah. (6 years of addiction and I gave him hundreds of second chances, rehab, private counseling, etc. It was all BS and his attempt to string me along.)
You really need to separate yourself from her emotionally and physically. It's time she did everything for herself. She'll figure out how to get from here to there. Part of that is ditching the secks (LOL took me a second to figure out what your were writing). She is trying to use that as one more hook to get you to stay with her and is trying to strengthen the bond. Al-Anon taught me about the need to compassionately detach oneself from the addict. You are not being cruel to her but you do need to set boundaries. Honestly bud, you aren't doing such a good job on the boundaries front.
Keep posting. I'm interested in your story and how things go for you.