When my XH left he said that he felt "trapped" and that he was leaving because he thought he'd been happier when he lived alone before we met. This sounds like the "pushing away" that you refer to.
My H told me that he had never really lived on his own before and needed to have that experience. I think he was 32 when he married his first wife! He certainly wasn't living with his parent until then.
My H seems to have multiple issues (some control, a little hypocondria, definite mortality, possible identity, etc...) going on but I'm not sure if they all stem from one source that appears he has never been able address. I wonder if he was able to some how deal with the underlying issue, then would his road blocks be gone and he could move forward? Can issues like this only be identified and worked through with C? It sounds to me the if someone continues to avoid the underlying issue, they will he remain stuck. Is this true?
I really have no idea what my H's underlying issue is. Childhood issues are always discussed here but as far as I know, my H had a fairly normal childhood...however he has acted very teenager-like during the crisis. My H's parents did divorce when he was around 19-20 but??? I can't help but feel there was some issue with my H's mother because he would always talk very fondly about his father but hardly mentioned his mom. I guess only he can figure it out.
It seemed like my H was gaining such clarity and coming toward me...now he hit a wall and ran away again. From what it appears, he is stuck in withdrawal and no nearer to acceptance. Oh well, on with my life.
I think he was 32 when he married his first wife! He certainly wasn't living with his parent until then. 
Oh well, on with my life.