I generally don't fold sets in sngs.

[runner4life7]

I think to suggest his range is only 66 is pretty crazy, yes he is solid but just 66 come on. Is AQ of diamonds possible? You can't assume he only makes perfect plays with only the near nuts because NO one plays like that. You might even learn something about this player by calling. I have also seen a lot of players playing AK a lot slower preflop, thats not out of the question.

Also, dont assume that folding your KK 3 times was correct because he had AA, it very well may have been, but because they had aces that time isnt a good reason why.