Fold Nut Straight on Scary River?

[revlis87]

Please dont criticize preflop...i do this almost never.

5-10 PP 6Max.

I definately have a LAG image and am doing quite well...I get the impression villian is a regular, not sure if hes LAG or TAG yet but I am 80% sure he's a winner by recognition of his name...I am playing under a new name - he doesnt know who I am.

Hero has 3h 6h and raises to 40 (standard). Villian calls in SB and BB comes along as well.

FLOP: Q 4 5 rainbow. SB bets out 3/4 pot, BB folds I call. ~ 330 in the pot.

TURN: 2. SB bets out again 2/3 pot, I call (easy shove next time, yes?) ~750 in pot

RIVER: 5. SB moves in for about 850. I fold.

I think my logic was bad... If i put him on a set I had to push the turn. As played, is river fold so bad?

Villian (Miles1215 or something like that) shows Q 10 and seems to know he just bluffed me off a big hand... Obviously his bet makes no sense but, aside from pushing turn is folding river so bad?