I don't want to get involved in the personal business between any two or three+ people, but I also do not mean to suggest that every arrangement that both parties agree to has a matching balance of stress and benefit to both parties. (Love your dream scenario! for me, that would totally be a nightmare.)

And I don't think any specific gender causes the harm for a pattern of gender differences, like a bias to favor male employees because people report more satisfaction with male employees.

But with a gender-based pay inequity, which couples benefit most? gay men, straight people, or lesbians?

And should we care more about couples than we do about individuals, eg: single women? I don't think anybody is suggesting this. But this is, in my mind, the primary problem with gender-based pay inequities, and 'innocuous' causes are no longer 'innocuous' if the harm to individuals is measurable and significant.