I'm really trying not to slowplay sets... honest... but after countless hands of crap like this resulting, it's getting hard

PokerStars No-Limit Hold'em, $0.10 BB (7 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($3.50)
SB ($12.85)
BB ($4.10)
Hero ($19.10)
MP1 ($9.45)
MP2 ($12.40)
CO ($8.10)

Preflop: Hero is UTG with 8, 8.
Hero calls $0.10, 3 folds, Button raises to $0.5, SB calls $0.45, 1 fold, Hero calls $0.40.

Flop: ($1.60) 7, 8, 6 (3 players)
SB bets $11.7, Hero calls $11.70, Button folds.

Turn: ($25) T (2 players)
SB bets $0.65 (All-In), Hero calls $0.65.

River: ($26.30) 3 (2 players, 1 all-in)

Final Pot: $26.30

Results in white below:
SB has 9d 9h (straight, ten high).
Hero has 8s 8h (three of a kind, eights).
Outcome: SB wins $26.30.

This looked like an obvious fold for me, and I thought about it long and hard, and my conclusion was, if he really hit a straight or flush, would he bet this much? Plus FTR tells me not to throw away sets to donk bets like this, so I made the call. What would you have done?