Thanks for replies,

I checked the river and he bet 27$ and I folded. I usualy bet about 3/4 pot on turn, when I suspect that somebody is drawing. But since I made that bet on the turn I also have to be able to lay it down when the 3spade fell. If he bluffed me or if he chased the draw and hit, well then he will be making less $$ in the long run IMO.