I think you re-raise the flop AI. I'm betting villain has a set and isn't giving your flush credit, or has a lower flush. If villain has a set, he could still draw, I'd rather get it on the flop regardless. If villain has a set, you could prevent him from outdrawing you, and if villain has a flush he'll stick it all in.

Villain seems to like this hand, why not? The next spade could kill action if the flush is low, or outdraw you by board-pairing.