In what way does Spade choose loyalty over Brigid in the final chapter?

It would be easy for Spade to fabricate a story to keep Brigid innocent in the eyes of the authorities. His experiences with women have taught him that women come and go, and today's the strong feelings could very well be dissipated next week. A man's loyalty to his partner, however, should take precedence over passing emotions any time, and Spade chooses the path of loyalty, another major theme of the novel.