River fold against maniac?

[sf340flier]

I continue to have problems against maniacs on the river. Normally, this would be an easy river fold, right? But against a maniac, I'm not so sure. This particular maniac has shown several bluffs to the table.

Button is 75/34/8.2 over 89 hands.

PokerStars 2/4 Hold'em (5 handed) converter

Preflop: Hero is MP with T[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, Button calls, <font color="#666666">2 folds</font>.

Flop: (5.50 SB) 9[img]/images/graemlins/club.gif[/img], 4[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, Button calls.

Turn: (3.75 BB) 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">Button raises</font>, Hero calls.

River: (7.75 BB) 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets</font>, Hero folds.

Final Pot: 8.75 BB