This is the second time in the last year I've worked up the courage to talk to a guy after a breakup. 

It's always the same story: these guys tell me I'm beautiful, we seem to get along well, we have things in common, everything is perfect and I get excited very quickly. I always think I've finally found someone I can trust. 

Then I see them suddenly lose interest. They become more and more distant, and eventually we give up on the connection. I asked them if they could tell me where I went wrong.and I got vague and polite answers: "you are a good person, but...sorry...I just prefer someone else". 
So where did I go wrong? 

Am I awkward or boring because my fear of rejection sabotages me? Am I too clingy and too easily attached because I crave affection? Is my behavior strange and BPD doesn’t let me see that?

I guess I’ll never know. Intense fear of rejection and lack of self-awareness in a nutshell.