Should I Make a Laydown?

[shipitfish]

I've been playing reasonably well lately, and been able to make pretty big laydowns. Here's a case where I failed to lay down the third nut full house when there was a reasonable chance my opponent held the nut full. However, I don't think that I made a mistake, but would like some input.

This hand is from a 10-handed tight online game, with $.25/$.50 blinds and no maximum buy in. This game was tight and passive, most flops were heads up if raised, but there was a good amount of limping. I started the hand with $213 and have the table covered. spcome, my heads-up opponent on the flop, had $59.90 behind.

UTG+2, I raised with 8 8. RoyRFlush called me, and spcome from the small blind made it $5.75 to go.

I've been raising lots with any pair, any suited connectors and two-gappers, and pretty much any hand I play, and I play tons against opponents this tight-weak. However, it's not common for someone to reraise from the blinds, so I actually gave him a tight range: JJ, QQ, KK, AA, AQ or AK. There is really no way he has something else.

I called for set value, since it's only 10% of his stack and most players on this site will stack off with any overpair. I flopped gin with 8 5 5. spcome bet out $9. I basically have him on an overpair or an AK continuation bet. I call with celerity, trying to represent a flush draw, and hoping it doesn't come if he has an overpair. The turn fell K.

spcome thought for a moment and bet out $7.50. This bet is basically narrows to three possible things: A K, KK, or a scared QQ, the last being unlikely.

I figure I should call to try to trap the A K.

The T brings any possible flush draw home on the river, and spcome led all-in for $37.65 into $45.25. I called immediately, figuring he's made a flush or he has kings full. My “muck or show” window popped up; he had K K.

I'm curious if others think this was just plain bad luck. I think the only other decisions I could have made were: (a) raise the flop against the obvious two-outer, (b) fold the river. It seems to me the spade falling on the river forces my auto-call because A K becomes as likely a holding at that moment as KK, given the action. I also don't mind my play on the turn, because I'm enticing him to keep coming at me if he does have AK. As for the flop, again, I think just calling is better in case it's just AK or AQ.

[ Update: for those who don't read comments, I'm convinced by swolfe's arguments that I should fold the hand on the river if I chose not to move in on the turn. ]