I don't think you want to risk giving him a free card on the turn here. What do you think he is likely to have?

I think you're ahead here and he's calling because he had a draw. Do you want to risk AK checking behind? Especially if he has the A[img]/images/graemlins/spade.gif[/img]. He could also have TT, and maybe the T[img]/images/graemlins/spade.gif[/img] too.

It's likely you are ahead here and it's also likely he has a few outs to beat you. I'd make him pay to hit them.