Sex and Chocolate: Complements or Substitutes?

The attached picture is a display at the local CVS in Ann Arbor, Mich. My thought was that this shelf display is a great example of complements: Enjoy a chocolate bar together, and who knows what nice things might follow?  My son thought that it depicted  substitutes — no luck in love, so drown your sorrows by eating chocolate.  I don’t know who is correct, but the example illustrates well the fact the complementarity/substitutability can depend on the specific situation being examined.