I haven't played in about a month so my instincts could be a little off here. My thinking is that there are only three hands that beat you, and only two are in his range (KT and KJ). He probably bets KJ on the flop so we can mostly rule that out. That leaves KT which makes sense and putting villain on one hand is something we are hardly ever supposed to do. The river 3 bet shows a huge amount of strength and is very rarely a bluff, but because of the weird way you have played the hand opponent could be spazzing out. I close my eyes and call.