OuttoLunch said it first and with fewer words, but I am going to second it: you may get much more out of a therapist at this juncture. This very topic came up at my NarAnon meeting this week. Sometimes we really need the one-on-one with a trained professional to help us stay the course in our recovery.
I just returned to a therapist again, and because of NarAnon, I can now keep what's relevant to that process there because I know my other important growth needs will get attention with the therapist. My hunch is that your deeper issues are much older than your current relationship. The grip on fear, waiting for chaos, not able to deal with normal & healthy--these point to other issues, at least in my (very familiar) experience. I learned to be codependent because of my childhood home scene & the trauma of the bigger world.
If you want to PM me, I can offer suggestions for how to find a therapist that will be a good fit--it can be so overwhelming finding one you connect with who is also well-qualified. In any case, all the best to you for your efforts to heal!
Two of us last week were stumped about Step 4 and the wise women there pointed out that we were actually DOING it already by the questions we were posing, so there you are, too! Hang in there.