Live 1-2 NL - flops wheel in limped pot - flush completes

[r1base14]

Here is the situation. I am sitting in a pretty juicy live game, 1-2 blinds, effective stacks are about 200, i have villain covered. I have 35o in the big blind. Few limpers and I check my option. Flop is Ax2h4h. I check, checks to LP player who is not great but definitely not a fish. I have seen him call off his stack in very questionable spots, and have seen him make moves at pots in situations where he thinks he can take it down, but nothing out of line.

LP player bets 10, I check raise to 35,he calls unenthusiastically.

Turn is the worst card in the deck, 3h, putting 4 to the wheel and completing the FD.

I check, he bets 40, and I call to re-evaluate the river.

River is 8c. I check with the intention of calling a reasonably-sized bet. He thinks for about 30 seconds and moves all in for 110. Total pot is about 170.

I tank, announcing that i flopped the nuts and flip over my cards. Villain peeks at his cards and I ask "Are you checking to make sure you have two hearts in there?" to which he only replies with a half smile that is definitely NOT a legitimate smile.

I tank for a while, he calls time, i wait for a few seconds and muck.

I figure that he wouldn't make that large river bet with 4 to the wheel and a three flush on board without at least a 5 , and most likely a flush. I almost called based on his reaction to my question about peeking at his cards, but I just couldn't see him making that large river bet without the flush. In retrospect, perhaps I should have block bet the river and folded to a raise.

Thoughts? Reactions? Recommendations?

Ryan