Love between the sexes begets a complacency and good-will, very distinct from the gratification of an appetite.
 David Hume, An Enquiry Concerning the Principles of Morals (1751). copy citation

Context

“Shall we account for all THEIR sentiments, too, from refined deductions of self-interest? Or if we admit a disinterested benevolence in the inferior species, by what rule of analogy can we refuse it in the superior? Love between the sexes begets a complacency and good-will, very distinct from the gratification of an appetite. Tenderness to their offspring, in all sensible beings, is commonly able alone to counter-balance the strongest motives of self-love, and has no manner of dependance on that affection. What interest can a fond mother have in view, who loses her health by assiduous attendance on her sick child, and afterwards languishes and dies of grief, when freed, by its death, from the slavery of that attendance?” source