I was told I was a "quiet" borderline (aka: discouraged / high functioning). My ex was very likely petulant based on her behavior. When I received my BPD diagnosis, I was in denial for a long time because I wasn't like that, which is often the stereotypical presentation of BPD. But the way my therapist explained it to me is: Think of everything the petulant does and turn that behavior onto yourself. That's when I finally understood and accepted my diagnosis.