Claire is feeling under the weather but has too much to do. Phil offers to help her out with her errands and pick up some slack until she feels better. One of the gains of partnerships is that if one person goes down, the other can pick up the slack.
See more: gains from trade, gains to marriage, risk pooling, risk sharing, utility
Mitchell complains to Jay about Cam being too nice, and Jay complains to Mitchell about Gloria not liking his dog butler. In the beginning of the scene, the two complain about the actions of their partners and how it imposes a cost on them that they feel their partner is not considering. Jay loves his dog butler, but he also doesn’t want to upset his wife. Cam spends a lot of time helping people and animal, but Mitchell feels it is sometimes a burden.
Jay notes that they are both with people who are very different and that maybe that makes their relationships better. The concept of interdependent utility functions is that people maximize combined utility of a household/relationship even though that means they way not be maximizing their own individual utility functions.
See more: assortative mating, gains from trade, gains to marriage, interdependent utility functions, matching, preferences, utility