Fold KK on rag flop - am I insane????

[MrMonkey]

15/30 party poker

Party Poker (10 handed) converter

Preflop: Hero is SB with K[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/diamond.gif[/img]. </font>.
5 folds, CO calls, Button raises, Hero raises, SB folds, BB calls, CO calls, Button calls.

Flop: 6[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/spade.gif[/img]
(4 players)</font>
Hero bets, BB calls, CO calls, Button raises, Hero calls, BB raises, CO folds, Button raises, Hero folds (?!), BB calls.

My thinking here when button made first raise was that button's raise is dangerous cause it's not a knockout raise, it must be for value or free card, since I felt in danger here and against probably str8 and flush draws I decided to wait for the turn where I was a bigger favorite and lead if it was no spade, 5, 7 or T.

But then suddenly BB wakes up with a hand and Button caps? The fad these days is to fast play sets and str8's, esp on a flop like that, and I figured best case scenario for me is that I need to get 2 more cards off without seeing A,5,7,T or spade. I figured I'd play it safe and fold before it got out of hand.

Any opinions? Should I go to showdown if no draws come? Should I at least see the turn? I don't have Ks so I'm definitely folding turn if a spade comes.