My husband and I have always been equal income earners, which was really important to me. (theeverygirl.com)
When it is expressed in units of production, the cost of production exactly equals the income from the sale of those units. (famemaine.com)
On the other hand, when the two spouses have more equal incomes, and they are both substantial, the odds of getting hit with the marriage penalty go up. (turbotax.intuit.com)