"And that's just one of them..."

I played a VERY embarrassing hand in my latest session tonight, so I thought I would write about it while the hand is still fresh in my mind. At the time at which this hand occurred, I had been having quite a difficult session. I was likely beyond the point at which I should remain in the game (both in terms of mindset and table image).

I make at least one blatant obvious mistake in this hand, but I additionally make one somewhat uncommon mistake (uncommon in the sense that the situation does not arise very frequently). It is this second mistake that I particularly want to keep in mind for the future.

SB is a smart, tricky, and aggressive player. SB is aware of Button's tendencies.
Button is a loose player who also almost always does not 3 bet with his big PP's preflop. Button's hand reading skills are questionable, and his opinion on what constitutes a big hand is questionable. Over the course of this long session, Hero and button have had a number of pleasant conversations and button is legitimately nice to Hero.
On flop, Button will always bet any pair when it is checked to him.

hand #1
live $20/$40 LHE
preflop: Hero raises UTG w AcKs, mucked to button who smooth calls, SB calls, BB mucks (3 players, pot size 7 small bets)
flop: AsQcJh SB checks, Hero checks, button bets, SB mucks, Hero calls (2 players, pot size 9 small bets)
turn: AsQcJh9d Hero checks, button bets and says "I've got it", Hero tanks and calls (2 players, pot size 6.5 big bets)
river: AsQcJh9dKh Hero checks, button bets and again says "I've got it, I've got it, I've got it", Hero tanks and mucks, button turns over one card, Jc, and says "and that's just one of them..." (meaning??)

Regarding the unconventional flop play: This was something of a fps (fancy play syndrome). Button will auto bet any pair (including an underpair), and SB will check raise any pair on the board if pfr checks. SB would slow play a hand like 2 pair or better by only calling. Hero's intention is to 3 bet the SB. When SB mucks, Hero smooth calls with the intention of check raising the turn.

On the turn, Hero becomes legitimately concerned about button's claim and conservatively calls.

On the river, Hero's muck with top two getting 7.5:1 is ridiculous as button's range is most 2 pairs or better. Doing a straight baysian analysis (J9, QJ, AJ, A9, JT, QT, KT, JJ, QQ, KK, AA) (dropped AK and AQ as he always 3 bets these preflop) shows that mucking the river to be a -2.64BB mistake. OUCH!

A big miss on the part of the Hero during the river action was ~neglecting to ask the button to show his hand~. With this type of player and this type of relationship between players, asking for a peek is extremely likely (perhaps 75% of the time) to result in one or both cards to be revealed.
If button even only shows the J, with the revised range, mucking the river is a -4.23BB mistake.

This is the type of scenario that arises with sufficient frequency in live game situations that I should keep the "can you show me?" play in my arsenal.