A slick too far?

I get awfully nervous when I see a four flush on the board, and my tendency is to fold/check if I don't have the suit ... even heads-up. I would guess this is a leak that could be costly over time. ... comments on this hand would be welcomed:

Paradise Poker 0.50/1 Hold'em (10 handed) FTR converter on zerodivide.cx

Preflop: Hero is UTG+1 with A[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img].
<font color="#CC3333">UTG raises</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">6 folds</font>, SB calls, <font color="#666666">1 fold</font>, UTG calls.

Flop: (10 SB) 2[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">UTG bets</font>, <font color="#CC3333">Hero raises</font>, SB folds, UTG calls.

Turn: (7 BB) 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
UTG checks, <font color="#CC3333">Hero bets</font>, UTG calls.

River: (9 BB) K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
UTG checks, <font color="#CC3333">Hero ?</font>