I totally agree with your strategy and that's what I actually do in most cases.

However it's still not a matter of worrying about AK, it's a matter of worrying about all sorts of goofy other hands that he might have (that make two pair or better).

That is why I capped it on the flop where I felt I was ahead, but then on the turn I choose to take the safe approach (after he raised), there's no way to know if the turn card helped him or not.

And for the same reason I certainly wouldnt of been the aggressor on the river where yet another card can help this guy. (which it did not that it matters)