Hi Sunsetbay and welcome.

First, I agree with "hereiam" about anyone self-diagnosing--- it would be good to see a professional to get a thorough evaluation. You might only have Borderline "tendencies" and not personality disorder.

And second, just because some people say they're loved one that is BPD has certain characteristics doesn't mean all BPD do. Like "LMO" said, these people posting such things are speaking through stress, being upset and dealing with a difficult situation for them.
You said---" It saddens me to think that I'm not capable of being nice when I have a BPD. "--- please realize-- they aren't talking about you specifically but their own SO.

My mother is BPD.... and I have to admit, my experience has been horrific to be raised by her. But you see.... that is her and I understand that not all BPD's are the same.

As I understand it....most people with a personality disorder-- have a dominate disorder with one or perhaps a few other disorder "tendencies". That's what makes us all so unique--most people don't just fit perfectly in any one diagnosis-- there could be one dominately BPD with narcissistic tendencies and yet another dominately BPD with histrionic tendencies. Or like me-- dominately AvPD with paranoid tendencies.

Who knows what your combination could be!!???

Wishing you well,
mandy