[Pokey]

You called preflop intending to get it all-in on a safe flop. Conditional commitment is good poker strategy. Good.

You checked the flop intending (I hope) to fold to a bet. Since the flop wasn't safe, you're done with the hand. Good.

After the turn did not change your hand you continued with your plan and folded to a bet. Good.

I see nothing wrong with your play here. It's safe, and at uNL safe is best. There's no reason to get mixed up with a total unknown with a hand that is frequently drawing to two outs. He could easily be bluffing with the best hand, here, and he could also be slowplaying a set, two pair, or AK. Sure, bluffs are a possibility, but when a total unknown three-bets I'm not wanting to continue when an ace hits the board and I don't have one.

Don't feel bad -- you made a safe play and avoided risking your stack when you did not have enough information to know whether that was a good idea or not. Without a read to the contrary, trust your opponents and avoid these unpleasant, high-volatility situations that are either narrowly +EV or extremely -EV.