New to 10/20 - bet this river?

[7ontheline]

Taking a shot at 10/20 after a decent run at 5/10 6 max - getting my ass handed to me so far, -55 BB in a very short time. It's just bad variance, I think, since my W$SD and W$SF numbers are horrible - anyway, the amounts of money seem large to me and I'm quickly losing confidence. Dammit. Should I bet this river? Any other diamond and I bet, but I was afraid only a better hand would call me. Should I have bet and tried to get an ace to call me?

Relevant reads - SB is extremely passive and pretty loose - he will call almost anything down, but not raise without a big hand. He'll fold complete crap on the river. BB is also basically loose with moderate aggression. CO is kinda sLAGy - haven't played many hands with him but I've seen him multitabling and he seemed solid over a limited sample.

Party Poker 10/20 Hold'em (6 max, 6 handed) converter

Preflop: Hero is SB with 3[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/diamond.gif[/img]. CO posts a blind of $10.
<font color="#666666">2 folds</font>, CO (poster) checks, Button calls, Hero completes, BB checks.

Flop: (4 SB) 6[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, BB checks, CO checks, <font color="#CC3333">Button bets</font>, Hero calls, BB folds, CO calls.

Turn: (3.50 BB) 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, CO checks, Button checks.

River: (3.50 BB) 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
Hero checks, CO checks, Button checks.

Final Pot: 3.50 BB