Economics of marriage is all about how money, resources, and decisions about money relate to marriage. It's about how two people in a marriage plan for their financial future and how those plans affect their marriage.
Basically, when two people get married, they make a plan together on how to pay their bills, save money, and invest. This plan can involve one or both people working, budgeting, and investing. Together they decide how to manage their money so they can pay their bills and save for the future. This kind of planning helps them take care of their family and make sure they can have enough money to live on.