Chapter 4 calls marriage a school. A husband learns realities of womanhood he could not know alone, and a wife learns realities of manhood she could not know alone. Love becomes educational, not merely emotional.
That means marriage is not only about confirming what each person already is. It is about being stretched by the irreducible otherness of the spouse. The spouse becomes a teacher in the curriculum of love.
This complements public-purpose accounts of marriage. Before a couple can widen love outward, they must first be transformed by the daily work of learning each other well.