You have two overcards and a flush draw against one opponent who has shown no strength so far in the hand, with just one opponent standing between you and this decent sized pot, you must bet and give yourself a chance to take it down right away, so a turn bet is mandatory in this spot. The real question is should you bluff the river or just check and give up, the pot is pretty big, and a bluff only has to work 13% of the time to be profitable. However, I would also check the river becuz your opponent is never folding a pair, and if he didnt have a pair on the flop (meaning he was likely calling on some weak gutshot draw) the turn card either paird or filled every gutshot/OESD possible with the exception of QJ which you beat anyways. So checking and giving up on the river is the right play IMO.