Where did I go wrong?

[sds4255]

Party 30/60
Hero is BB with two black bullets. UTG1 raises and everyone folds to the button who 3bets, I cap and UTG1 and Button call. Flop 722r. I bet UTG1 raises and button folds I 3bet and UTG1 caps. Turn is the j of hearts, I bet UTG1 raises. I call. River is the 6 of Diamonds. I check, UTG1 bets I call, he turns over 72 off. How? And Why? My stats say he is a rock.