Villain is 49/38 with 13% 3bet over 80 hands. I've only seen him get 3bet once before, and he 4bet. He has opened 74% of cutoffs so far.

Postflop, he doesn't seem spewy so far. His AF is 1.8 and out of 5 times I've seen him face a cbet, he's only raised once. He's called 3 times, and folded once.

We're so deep here, and he can have all the sets, so I folded, but I wonder if this is really bad in a 3bet pot?

Even if he's crazy enough to be raising all his overpairs as well as sets (which his stats don't really suggest he is), I'm a slight dog, he has to be raising all his overpairs and sets and at least 8 bluff combos for me to be slightly ahead.

Poker Stars, $0.10/$0.25 No Limit Hold'em Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.

Hero (BTN): $60.57 (242.3 bb)
SB: $43.11 (172.4 bb)
BB: $32.60 (130.4 bb)
UTG: $26.01 (104 bb)
MP: $18.85 (75.4 bb)
CO: $102.59 (410.4 bb)

Preflop: Hero is BTN with K K
UTG folds, MP raises to $0.50, CO calls $0.50, Hero raises to $2.75, 3 folds, CO calls $2.25

Flop: ($6.35) 6 T 9 (2 players)
CO checks, Hero bets $3.75, CO raises to $9.70