But historically, two income households have not been common. This is a recent (past two generations) turn of events. I agree that a marriage-based tax break

But historically, two income households have not been common. This is a recent (past two generations) turn of events. I agree that a marriage-based tax break may not have been sensible, although now with gay marriage legal nationwide, as long as the government also recognizes civil unions, it may be ok and solve the part of the problem you note.