What was your thought on the flop play? You raised 4BB PF, he came out betting the flop for 1/10th of the pot. Okay the flop is as scary as it could be, but your opponent isn't showing much confidence in taking this one down by betting this little. Besides the occasional slowplay, you are pretty much ahead of his range. If he had the nuts he probably bet a little more on the flop since your position rules out some weaker raising hands and this board has most likely hit your hand in some way; (nut)flush draw, straight draw, two pair, 2nd pair, TPTK or a set. I think this is a WA situation and you had to make him pay for any draw he was trying to hit, raising him half the pot to 3/4 of the pot.

By just calling his flop bet you put yourself in a pickle with that river card. Good example of a dark tunnel bluf that flop bet of his.