raising here is just a bit greedy Brian!!
You know he only calls/raises you if your beat. There are a select few hands he may pay you off with, but not enough to be value raising the river with. He pays you off with 55/AK (maybe) AQ (less likely)
Like somebody said its possible he has a 6 and was betting out the straight draw on the turn although id like to think he'd do this on the flop...
So if you think that he could be bluffing there is no need to raise, your not extracting any more value out of the pot, you have a made hand so there is no need to raise, If you raise you are opening yourself up to a re raise which will spark a lot of trouble as you know and as you found out.
The range of hands that you beat and the range of hands that have you beat do not make it valuable to raise here in my opinion. Good luck in Monte mate
i dont think so, he could make a bet w/ AK, AQ, and pay me off! I had played very weak to him all day, he was arrogent and I thought I had him, not so easy Mr ben, still love ya

You have been playing weak, even more reason not to raise on the end as he finds it easier to fold AAA