Mac,
Many states had laws against adultery, with varying levels of punishments and enforcement.
A quick search..... 16 states: Arizona, Florida, Kansas, Illinois, Massachusetts, Oklahoma, Idaho, Michigan, Wisconsin, Minnesota, Utah, New York, Mississippi, Georgia, South Carolina and North Carolina. Reveals that some states still have them on the books.
Various groups who need to maintain unity also expel or punish cheaters, the UCMJ can be used to punish cheaters, outlaw biker MCs forbid anyone from touching another members old lady. The Mafia appears to have had rules against adultery as spouses know too much and see too much. I would guess many religions still view it as a sin.
I think in the liberal west we have lost sight of the fundamental importance of the family as the building block of society.
We mock other cultures for stoning adulteresses, but we miss what values it is meant to support in those societies.
As you describe it in your marriage it was a form of child abuse, yea isn't that against the law?
What about the breaking of the marriage contract, shouldn't that retract the financial rewards offered by marital law?
We enforce laws about property, but allow the damaging of human lives without consequence.