Game is good at the moment and not much preflop raising going on. I have a deep stack (about $1100) as does much of the table. I limp in UTG+1 with Ac 2c. Two more limpers behind me, SB completes, BB checks. SB generally plays loose and passive. I don't know that I have seen raise before the flop in over 2 hours of play with him, and he tends to do more checking and calling than betting.
Flop comes Ad Ah Kc. He bets out $45, BB folds, I call, other two limpers fold.
Turn is Ts. He bets out $125, I call.
River is 6d. He bets out $250. I tanked for a while, but ultimately folded. FWIW, I planned to check behind the river if he checked.
My river thought process was that he has at least Ax and that he's not capable of firing a big bet with Ax to try to get me to fold a chop. I think he would generally be scared if his kicker didn't play, that I might have boated up. I didn't entirely discount chopping Ax, but I weighted them down enough that I didn't think I was getting a good price to call.
i call the river. it's a chop much more than you're beaten imo. he doesn't sound good enough to bet to get you off a chop, so i think he's betting because he has three aces and thinks you'll call with worse.
You could raise the flop and take control of the hand, getting a free river showdown when he goes into calling mode. If he leads into you despite that level of aggression, then your fold might be more warranted.