seems to me this man has some control issues - doesn't like and likes being in control. likes being in control - taking you from behind. doesn't like being in control - won't initiate sex or respond in any obvious way while you are the agressor.
is he trainable? only if you share with him and he is willing to share. i wouldn't want to do all the work either!
my husband is pretty naturally quiet and too, and personally i've always thought it was a bit of repression (catholic upbrining & all) - but maybe not, maybe people are just made differently.
so.... bottom line - do you love him and do you want to communicate with him? what you said at the end about his 'not caring enough to expand his sexual horizons' to meet your desires - does that carry over into your non-sexual relationship?