Flush hand. (100NL 6-max)

Villain is 43/7.

Party Poker No-Limit Hold'em, $ BB (6 max, 6 handed) converter

MP ($39.90)
CO ($236.05)
Hero ($104)
SB ($116.52)
BB ($143.68)
UTG ($27)

Preflop: Hero is Button with Q[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.50.
UTG calls $1, <font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises to $4</font>, SB (poster) calls $3.50, BB calls $3, UTG calls $3.

Flop: ($16) 8[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">SB bets $15</font>, BB folds, UTG folds, <font color="#CC3333">Hero raises to $40</font>, SB calls $25.
<font color="green"> Weak raise?. My only explanation is I had my eye on his whole stack, and was planning on getting it in on the turn. Once he calls the raise I put him on a set or maybe an A [img]/images/graemlins/diamond.gif[/img]? </font>

Turn: ($96) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero checks.
<font color="green"> My plan after the board paired was to check/call the hand down. </font>

River: ($96) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB calls $72.52 (All-In), Hero folds.

Final Pot: $168.52

Obviously, on the river I figured I was most likely behind. How bad did I screw this up and why?