"And I've been thinking, I was the HEALTHY partner!"
There's narcissism within all of us, or we'd fail to get our physical needs met, while we're occupying space on this planet. It's just a matter of degree, as to whether our narc traits are constructive or destructive.
The Codependent, the one who compulsively tries to take care of everyone else's needs and feelings, is grandiose, due to believing he or she can 'fix' others and resolve their difficulties.
It's crucial to realize, that in a relationship dynamic, the one who NEEDS THE LEAST, is always the one in the power seat. Therapists are prime examples of people who need to be in the one-up position in all their relationships~ they even try that shit within therapy sessions with their clinician~ often by volunteering information that is not solicited, nor helpful to their healing process.
The compulsion to stay very busy and preoccupied with helping others, often takes the form of Alexithymia ~a clinical term used to describe the compulsion to remain in motion or always BUSY taking care of another's whims, desires or needs. This results in people-pleasing behaviors that extend to obnoxious over-giving, while ignoring the needs of the Self.
Alexithymia (I call people who have this dysfunction, "Busy-Bodies, in my writings) is NOT a noble disorder, though it's thought to be, by people who engage in it. This is merely a way for the narcissistic individual to sidestep and dissociate from his or her own inner emptiness or pain, while feverishly attempting to rid another of theirs.
I've always tried to be even-handed in my BPD articles, showing you the other side of the coin, in terms of dysfunction that MUST exist within any individual involved with a Borderline or "malignant narcissist," which is long-speak for an especially toxic Borderline. ALL people with BPD traits are narcissistic. Not all are end of the spectrum, and dangerously destructive.
I think the article introduced to you here, explores the dynamic between the narcissistic Borderline and narcissistic Codependent (fixer/rescuer) very thoroughly. It's a lengthy piece, and will be published in book form before long, but it's worth reading a few times, so you can grasp the nature of the dance you may be doing with a severely impaired lover, while telling yourself YOU are the "healthy" one.