Make an exact analysis of what takes place within you when you desire anything. You will find that your desires are nothing but curiosity, and this curiosity, which is one of the forces of the heart, satisfied, our desires vanish. Whoever, therefore, would hold a spouse or a lover, should leave him something to be desired, something new should be expected every day for the morrow. Diversify his pleasures, procure for him the charm of variety in the same object, and I will vouch for his perseverance in fidelity.