Hello,
As per your description of the players all being good, you have flopped a monster and hit your nut flush on the turn with not much behind. As such, I will not fold in that situation with so much money in the middle.
That said, I would have played the whole hand differently from the beginning. I’d assume all 3 players entering the pot has an effective stack of $400. The EP raise to 12 is 6bb raise and i will proceed caustiously by calling pre. All 3 players are only 200bb effective and not deep enough for you to 3b. You are lighting your money on fire and forced to fold to a 4b.
After you 3b pre and going 3 ways to the flop, and the MP leading, I would just call as you want the EP to over call with any hand in his range.
In hindsight, it obviously is tough to say I will lay down if I played it differently from you, I would say your play in this hand is very aggressive and will tighten up a little playing with solid players.
Thanks for sharing, good luck on the tables.