The concept that a man can even “cheat” on his wife is a modern idea.
It violates the agreement he had with his wife. Modern expectations are that you do not commit infidelity.
He created a stable environment to have and raise his children and to provide for them and to contribute to his society. It’s not his fault he happens to live in a particular era where it’s otherwise not possible to do that unless you enter into some contrived modern notion of marriage where otherwise in previous eras there would be no issue.
Just to be clear, fertility rates in the developed world are nearly universally below replacement so there are various norms in place that are clearly not compatible with life.
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You know what else is a "modern idea"? That you can't sleep with a 12 year old and that you can't own slaves. Both were considered normal for most of human history. So I guess they're ok too, by your logic?
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