What does this excerpt from shakespeare’s twelfth night reveal about duke orsino?

duke: if music be the food of love, play on,
give me excess of it; that, surfeiting,
the appetite may sicken and so die.—
that strain again; —it had a dying fall;
o, it came o'er my ear like the sweet south,
that breathes upon a bank of violets,
stealing and giving odour.—enough; no more;
'tis not so sweet now as it was before.