Small Stakes No-Limit Hold'em

Heads up .. small blind limps.. I raise him up to 4 bucks .. he calls.. stacks are 48.. pot is 8 on flop… spr is 6..   flop comes out A Q J .. two spades..   he bets out pot on flop.. donk bets it.. i call flop… no spade or good card for me.. he bets pot on turn.. we have went over committment threshold and i'm willing to call down all in if i have too..  he bets river i call.. 

He has two pair.. qj.. but mathematically i should usually call cuz  without betting close to an spr of 13 too some extent i'm mathematically committed??

Problems is alot of average players almost never 3 barrel bet on anything worse than two pair or better right? 

mike