I make a crying call. You are probably beat, but at least it sets a precedent that you can't be bluffed on the river. Also, it gives you some information as to how the villain plays. If he called down with 2 overs all the way to the river make a note that it will be very hard to push him out in situations like this. Also, note the c/r for future hands one way or another. You will either find out he c/r bluffs or c/r when he hits his card on the river.