Why does Gallimard want to see Song fully naked?

Galimard claims, that it would remove the final boundary between them, but truly Gallimard needs what he calls "revenge." When Gallimard cannot establish dominance at work (he is told by Toulon that he and his reputation are on the line), he knows there is one place he can feel like he has power over everything he does. The only thing Song has denied him up to this point is seeing her naked, and he wants to make the final leap to establish his rule over his woman, and in turn, his life.