my boyfriend (22m) and i (18f) are in a long distance relationship &amp; it’s been 6 months. he is a super loving and affectionate person but sometimes the smallest things he does makes me convince myself he doesn’t care about me or love me anymore. 
in the moment i truly feel like i have to leave and protect myself from being hurt  &amp; i stop caring and say really mean things. i block him on everything and he usually reaches out through different numbers or emails begging me to take him back. and i do, because it almost validates that he does want me(?)
i feel really selfish  because of my behavior and i can’t help but feel like he’s sick of me. i really don’t know why i feel this way when he always reassures me and understands / is willing to work with me.. this is my first real relationship too. 
none of my friends know about my bpd so i just wanted some thoughts on what i should do. i feel like my behavior has been exhausting to him so i brought up ending it overall but he refuses and really wants to be with me. how can i overcome these urges and stop ruining something i really care about?