@Sighs,
I very much believe there is a healthy supporter and a co-dependent supporter. I personally don't have much experience with a healthy supporter (partner), but I do have experience with the co-dependent variety. I do not believe that all supporters are merely co-dependent!
As a sufferer, it isn't easy to tell right away if a supporter is healthy or not. Many sufferers have received NO support, so when a co-dependent supporter comes along, we are blinded by the flashy lights of *support* (ha) and don't immediately recognize that it is a dysfunctional, manipulative kind of support at best.
I think that sufferers really do have to keep their eyes open and know what healthy support is vs. unhealthy support. At first, my guy seemed so supportive. He wanted to learn ALL about PTSD, asked me if there were books that he could read, etc. Of course I was thrilled, as nobody ever showed such an interest in helping me before! Honestly, it was a mutual friend of ours who first showed me the cracks in the façade. She told me that he treated me as a "project", something to fix. Of course, this all fits in with his own alcoholism issues (which he is in MAJOR denial of). Fortunately I knew a bit about codependency and alcoholism, so the pieces started to fit together for me pretty quickly. Someone without this existing knowledge may not realize that such support is indeed unhealthy.
After just one month he was telling me that the honeymoon period was over. (As if...) He said that it was now the time when the hard work began....Uhm, I'm sorry, but if things go south after just one month, I'm most definitely NOT hanging on! (I didn't....Things fell apart in July, the guy called me on New Years to profess his love for me yet again. I was having none of it.)
So I guess my answer is that a sufferer REALLY has to be in a good place or they will much more readily accept unhealthy support. You really have to trust your gut, and as soon as a red flag pops up, be willing to question it and even walk away. There are so many predators out there, so many people who use other people that they deem to be "weaker". They lure us in by pretending to care and nurture us when the truth is that they want us to stay in the weak and submissive role as they fear being cast aside if/when we become "strong" again.