88 3bet from sb

[nadical]

villian is a 70/10/.7 who I followed up from 5-10 and I am pretty sure he is tilting as ive seen him make some awkward raises vs the lag next to him.
Party Poker 10/20 Hold'em (4 handed) converter

Preflop: Hero is SB with 8[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">UTG raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">1 fold</font>, UTG calls.

Flop: (7 SB) 7[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, UTG calls.

Turn: (4.50 BB) J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, UTG calls.

River: (6.50 BB) 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks

I really didnt feel comfortable bet folding as it hought he was tilting is bet calling a better option than check calling? Turn bet is good right?
Sorry if really standard

[wackjob]

Bet/fold the river. Since he is passive he is not likely going to raise you w/o a really big hand, and since you have come this far you want to see a showdown. Check/call lets him get off w/o paying the river when he has A-hi or a smaller PP(unlikely).