Marriage is, first and foremost, a contract between two parties, husband and wife. And this contract is originally set up to last for all eternity — till death do them part. As such, two married people (Family, in the following) form an economic union with responsibilities deriving from the contract, if so specified explicitly, or from societal norms accompanying it (yes, including current Zeitgeist, and prevailing moral concepts), and their union’s main purpose is to control reproduction and property.

From the fact that a family is set up to be ever-lasting, the main purpose of controlling reproduction and property, and basic economics, we can derive a few things:

  1. Any one person is either member of a Family as defined above, or not.
  2. A family can allocate their resources (labor or capital) to produce goods, and either consume them, or invest (“save”) them.
  3. A family can engage in (re)production.
  4. Derivative from 2 and 3: A family will engage in long-term planning to optimize their inter-temporal resource-allocation. Depending on future time orientation, this planning horizon may span a few weeks, or a few centuries.
  5. A family that engages in long-term planning can probably be relied upon in/by another family’s long-term plans, given coincidence of wants.
  6. Derivative from 5: Families can engage in mutually beneficial trade with other families.
  7. Derivative from 4, 5 and 7: In any society, Families can form cartels, to exclude less-reliable parties.
  8. Derivative from 8 and 4: Any one single person will be found less reliable than any one family, cartel-breakers notwithstanding.
  9. Cartel-breakers will benefit in the short-term, and be punished in the long-term. Bear in mind that the famous “Bromkonvention”-case study, which Libertarians like to harp over, does not work in real life. Cartels form all the time, for mutual benefit.
  10. A family member (husband or wife) can suspend the marital covenant, and engage in cheating (“cheater”, in the following)
  11. Derivative from 10 and 1: Any one cheating family member (“cheater”) must do so with either a non-family-member, or a fellow cheating family member (“cheater”).
  12. For any cartel to remain stable, cartel members must be in a position to force high costs on any cartel breaker.
  13. Derivative from 6, 8, 9, and 12: Families must levy a high tax on whoever is discovered cheater, or enabler of cheaters (It *does* take two to Tango).
  14. Currently, the divorce laws enable “no fault divorce”, with basic separation of economic goods (aka, “She gets half.”)
  15. Even if women bear no children, women typically earn less during their lifetime. However, for equal qualification and ambition, women earn the same.
  16. Derivative from 14 and 15: The introduction of no-fault divorce laws has weakened a man’s position to get away with cheating, without losing half his Family’s assets. In other words, he loses more than he contributed to that marriage, on average.
  17. Derivative from 14 and 15, pt 2.: The introduction of no-fault divorce laws has strengthened a woman’s position to get away with cheating, all the while retaining half her Family’s assets. In other words, she gains more than she contributed to that marriage, on average.
  18. Publicly known cheaters, and their enablers, will be discriminated against economically (in matters as obtaining income and credit).

Cheating, like lying, doesn’t pay off.

QED.