When did I develop a knack for this?

I was recently told that I'm quite adept at pushing others away. I'll find a perfectly rational, logical reason to explain why I shouldn't do something or be near to someone...and poof. They're out of my life and I move on - I've justified it to myself, left myself nearly blameless and I move on. I find ways to paint myself as the martyr, or the one to know better...I'm starting to wonder if this fickle defense mechanism of mine is something that should be dealt with - and how. It's hard for me to imagine finding what I want in life when this is how I react to the thought of anything long term. Once I get to that point in my train of thought, I usually bury myself into work or school or a book that colors a picture of adventure and love - one I wish I could simply dive into, with the words already stipulating what I'm desperately searching for. Adventure...there are so many trips I want to take and risky things I want to try. I keep debating whether or not these are things I want to explore independently or not. There's something to be said about accomplishing something significant on your own. I feel like I'm in a stage of self-discovery to be afforded that ideal of independence. Anything contrary to that ideal gives me a feeling of claustrophobia - I feel nothing short of stifled and almost panicked. Once I recognize that feeling, I can't help but berate and detach myself from situations. I'm trying to curb that cataclysmic habit - it'll be the detriment to my finding any happiness in the long haul.