Thanks everyone.
No questions re calling on the turn - RosaParks summed up how I felt - though I see betting more on the flop and/or turn would make that decision even clearer - thanks Answer20.
Massive, I think he has mostly draws here (66, 77, 78, 79, 7T, J9, JT, KJ, and any two spades). I discounted made straights and sets a little since he just called the flop with the flush draw on board. He puts me mostly on overpairs or AKs and probably feels I am rarely strong enough to call the turn bet. And if I do he has outs.
As it turned out, he had 76o and we ran it twice. He scooped and I went home early and got an extra hour of sleep