PDs often attract each other, feeding into one another's dysfunctions. You sound like a codependent. Trying to play detective and therapist when you should be protecting yourself and having firm boundaries. People with PDs that have become malignant typically hone in on codependents with low self-esteem. It is important that you focus more on why you are behaving the way you do, because that is the only thing you can change.

A good read for you:

The Dance Between Codependents & Narcissists | World of Psychology