I have 9spade 5 heart He has 9clud 2heart The board is Ah 9h 7h 6h 3h Is it a split pot our does my 5h beat the boards 3h for a better flush.
Your flush beats his flush, because you make the better 5-card flush combination:
As you see, you win because one heart of your hole cards is used in combination with the board, givin a better 5-card flush combination. He doesn't even use his extra 2♥ hole card since the board has already
higher ranking cards, therefore his best hand is the entire board, but you're instead improving the board with your hole card.