https://en.wikipedia.org/wiki/Marriage_penalty
> If the incomes of the two persons are similar, then at the lower end of the tax schedule there is no difference between filing as singles and filing as a married couple (ignoring the question of deductions, see below). But at the higher end of the tax schedule, there is a penalty for a married couple whose incomes are similar, compared to what they would pay as singles.
https://www.fool.com/taxes/2018/11/15/the-irs-marriage-penal...
As far as I know at least.
> I am not sure what the rationale for marriage affecting taxes in the US was originally, but it doesn't make much sense to me.
I assume it’s because at the time the tax brackets which penalized dual high income earning households were decided, they weren’t politically powerful (or numerous) enough to push back on them. Nowadays, dual high income earning households are more common and they had the ability to get the brackets changed.
What you describe was middle class white femalehood ideal - what was supposedly happiest setup. But that setup was impossible for quite a lot of families, plus some families choose different setup. And some women were single or their husbands die.
But the actual labor participation was much higher then what the ideal suggests.
But it is interesting how around 40% women working morphed into women were not working which morphed into idea that working woman would be rare.
Does this offset the risk of divorce?