I think your flop bet tells the vilian that you probably don't have AK.... so on the river he can reraise you all in because he is only loosing to AA .... any other hand is a split pot or he is winning ........ if he has an Ace... if he has QQ he maybe gambling on you having QQ aswell ..... but if he thinks you don't have AK or KQ... what do u have AA QQ JJ...AQ.or AJ.
Dom