Well, I feel your pain, but keep in mind that you had 2 people chasing you there. They probably don't both have Aces, so you can count on at least one guy on a flush draw. I would have checked on the turn there too, instead of betting.

I think a feeler bet can be reasonable when you are heads up, as long as you keep the bet amount from getting too high (for example, just bet whatever you bet on the flop again, even though the pot is bigger).

With a multiway pot and a flush draw on board, I think you have to be ready to throw your hand away if the flush draw hits though.