If there are children involved and one person is doing more of the childcare that's totally different, also barring disability and such.
But if there aren't any... I've heard of situations where one party (usually the man) earns well. The woman maybe less, or just works part-time or not at all.
However since people 'should' pool money when married, the woman has access to the same high earnings as the man for little of the work.
I would love to swan around with access to a lot of money and just work part-time. I haven't got that luxury and probably never will.
It's just one of those things in life I suppose. I probably sound resentful, but I am. If it were a high earning woman marrying a much lower earning man, people would be calling him a cocklodger and saying he's taking her for a ride. However the other way round it absolutely must be shared finances as they're married. I don't get it.