Has anyone ever had a relationship with someone who has Borderline Personality Disorder?

I am confused right now. My ex broke up with me for the gazillion time. He hates me and then he can't live without me and then he hates me again. The reasons for him breaking up with me are outrageous. He demonizes me like I'm the worst human being on the planet, always leaving me feeling like "what the hell just happened?" Many times I think things are going smooth and then WHAM!! he says I don't love him and I'm not happy with him and he insults me. Everyone is shocked because everyone who knows me says I am the easiest person to get along with so they're confused as to why he would put me down all the time. He says I have no personality, and I'm not a happy person, and he's not having fun with me. I don't get it! None of these things are true. Why is he so mean to me one minute and then he says he loves me to death and is mean to me again! I was told he is Borderline. Does anyone know anything about BPD's?