So, he had you to confide his problems and now that he has a girlfriend he wants to cut off his relation with you? Only this speaks out loud.
I know how difficult and sad is for you, because he was your “favourite person”, I know what it means, but he wanted to put you aside, apart from his life. I know how hard it is for a “normal” person and I know it’s five times more difficult for a person with bpd, but kick it *** quite far from your life.