I know exactly what you are saying. I have thought I have BPD too because most all the things apply to me except the outbursts of anger. I keep everything inside and don't show emotions well, and I don't get really angry, well I do sometimes, but no one will know i am. So I have been not sure if thats what I have or not too.

But to be considered to have a personality disorder, most the time, not EVERYTHING will apply to you. I have found that out. If the majority of the stuff is the same/similar, then it is most likely you have it. I would say you do have it. Even though unstable relationships is a major part of BPD, that is only a part of it. All the other stuff still counts towards it too, Just that the unstable relationships and stuff is the most common or most known for BPD.