Does it not depend on his perception of you and what your range is in his eyes? Does his bet on the end always amount to air or the nuts. What I mean is, is he really trying to value bet on the end and if so what hands does he think you have that call, that he beats?
If his hand has showdown value, isnt he always checking behind on the river? Or can he turn up with the King after betting previous streets. This being said does it make your 22 a call always as he is more likely to have nothing than nut hands?
Basically as you can tell I havent got a clue but I am trying to understand the thought process behind both your call and his betting as it is no doubt deeper than I am able to think.
Cheers