Lost on this river

Villain is a multitabling nit. How does he have the nuts here? Wouldn't TT/77/22 play differently at some point? I guess if he's truly a nit then 22/77 wouldn't raise at any point. Why would a nit value bet a worse flush on a paired board?

Ultimately I let my post-it note override my logic, and I folded.

Full Tilt Pot-Limit Omaha, $0.02 BB (5 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

SB ($2.88)
BB ($3.24)
UTG ($1.97)
MP ($2.82)
Hero (Button) ($2)

Preflop: Hero is Button with 5, 8, A, 9
UTG calls $0.02, 1 fold, Hero calls $0.02, 1 fold, BB checks

Flop: ($0.07) 7, 10, 2 (3 players)
BB checks, UTG checks, Hero bets $0.07, 1 fold, UTG calls $0.07

Turn: ($0.21) J (2 players)
UTG checks, Hero bets $0.14, UTG calls $0.14

River: ($0.49) 2 (2 players)
UTG bets $0.49

Sucks but you probably have to fold. On one hand how does he have the nuts, but on the other hand what else can he have that gets to the river and decides to bluff?

He check-called a pot sized bet twice. Would the nit villain do that with 2 pair or a flush draw? Which is more likely?

He did limp into it. He could have 22, 77 or maybe TT. That's what happens when you limp.

I would fold.

I like the flop bet and if you don't take the free card on the turn I like a full pot bet more than the 2/3 pot bet.

As played I don't fold the river. Just call and say whatever.

On preflop, don't let these players limp UTG on your button. Raise them!

why would he take a free card holding the nuts on the turn?

its an expert level of thinking i presume, check the nuts with a redraw to the nuts..

uber deep level thinking

thats a great question. let me think about that one.

Chances that he's bluffing here are just about zero.

I'm surprised at how often I see players at micro stakes "slowplaying" hands like top and middle set on drawy flops. He might have check-called the flop with top set to avoid scaring everyone away, then realizes his mistake on the turn and decides to check-call again now that he might be losing, and then leads out when he hits his boat.

This is possible. It's also possible that he backed into a weird two pair and made a boat while chasing some other draw. I think against an unknown at this level, the river must be a fold. If you have a read that he's a donk who would bet a non-nut flush for value or make a random bluff, then call.