big pot, river fold

[jt1]

PP $1/2 6 max

SB hasn't shown any excessive aggression.

Hero is UTG with A [img]/images/graemlins/heart.gif[/img] 7 [img]/images/graemlins/heart.gif[/img]. Hero raises
MP calls
SB calls
BB calls

(7 sb) 6 [img]/images/graemlins/club.gif[/img] 7 [img]/images/graemlins/diamond.gif[/img] 3 [img]/images/graemlins/diamond.gif[/img]

SB bets. BB calls. Hero raises. MP calls. SB raises. BB folds. Hero caps. MP folds. SB calls

(8 bb)K [img]/images/graemlins/diamond.gif[/img]

SB checks. Hero bets. SB calls

(10 bb)9 [img]/images/graemlins/club.gif[/img]

SB checks. Hero bets. SB raises. Hero folds.

I felt comfortable folding this as I had no reason to think that I was up against a LAG or a superstar. Still, the pot is enormous, and if folding is incorrect then the leak is one I can't afford to have. Looking back on it,though, I think villian caught a set on the river. Comments on all streets would be appreciated.