Narcissism has a terrible negative taboo associated with it, and rightfully so, because it can drain the living shit out of the people close to the narcissist. But you have to be careful not to be even harder on yourself about it. Because that's how a narcissist would understand a character defect (i.e. "oh I'm a terrible person worth scum"). For me I've found the very first thing I had to understand was yes, I'm a narcissist, and that's terrible, and I need to fix that ASAP, but, forgiveness is not only possible, it's necessary.
With that out of the way, I cannot recommend Alexander Lowen enough. After years of research and self-exploration I've now landed on this guy and his thoughts. Check out his book Narcissism: Denial of the True Self.
One of the reviews on that page summarizes it very well: "Narcissism develops when children are made to feel rejected, humiliated, and powerless, at the same time seduced to feel special"
Edit: If that specific book doesn't appeal to you, see if any of Lowen's other books resonate with you more
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