Thanks for the question, and I’ll probably not answer in the Q&A because I’m not sure I’ve got much to say about it that might shed new light on the problem.
Are we talking about aspertame? I’ve heard it can be very highly addictive, but I have no personal experience with taking control and none that I can remember via clients.
If it was me, I’d do a tapering off to start with, to see how that goes. If abstinence seems the right move for you, by all means take that path. This is most certainly what I recommend to smoking clients: “all or none” is the way to go, and make choices moment by moment, rather than “never again”.
Let me know how it goes.