I don't think you need to worry about how you affect the therapist and his staff. It is their job to handle it. It also sounds like you have come quite far, more aware of the patterns and problems. I think it is a great idea to do your own reading/research, that way you can have all the time to consider what applies to you and what might not be relevant to your situation, instead of just relying on your treatment providers' feedback.

I get how hard it can be to accept a condition you are afraid of and really don't want to have, especially one that is associated with so much stigma and judgment. My version wasn't BPD or other personality disorders, but addiction. I was never diagnosed formally because I did not even seek any help and just tried to deny and fight it for many years back in my early 30's. I don't even fully get how that could happen, how my mind could be so brainwashed by my own denial as the signs and symptoms were all there, and pretty severe on top. In retrospect, I wish I could have overcome the denial much earlier and started working on recovery seriously - I know as fact it would have been much easier to resolve it had I not allowed it to progress so far, with so much damage, some irreversible. I know addiction is different from BPD, just bringing it up as another example for a very difficult condition to have and heal from. In part, I fought it so hard in spite of very clear symptoms because otherwise I am one of the most independent, autonomous persons I have met... how could that happen to me, of all people? But the fact is, these things are beyond out wishes, conscious control and we do not choose to have them. But we can choose to be aware and handle them better.

For me now, diagnoses are usually quite helpful because then I know what to work on and can try out many things recommended for the condition, or just work on it in my own ways... but I can focus on a real issue, not distractions and denial my mind wants to make up to mask problems. Some of it takes really dramatic life changes that have to be permanent, and it can also be hard to accept these limitations and the facts it will likely always require some work to manage. But so worth it in the long run!