*grunch*
preflop is ok.
Betting out on the flop is ok. You can't really protect your hand even with a checkraise if button open-bets if it is checked to him. You are best here often and you want to make sure that this flop is not checked through.
I do not know if you tried a check-raise on the turn. But I think you are far too timid if you are scared of a made flush now. You are risking to give any lone heart a free shot at a backdoorflush. If you are behind, you have 4 outs to a fullhouse. You will have enough Qs and Ks that pay you off most of the time. So I think you are betting for value on the turn here.
Same goes for the river. The river-card is a blank and I don't see any reads that might justify the assumption that one of your opponents is slowplaying a set or a flush. So I think you left a lot of money on the table with this hand.