If both partners make the same amount of money then they should contribute equally to bills. But if one partner stays home to take care of kids, if one partner is disabled and can't work, if one partner works a job that doesn't pay well and the other partner is supportive of this choice (perhaps because it's artistic), or (as in my case) one partner is incarcerated - this option isn't always possible. In such cases, it's important for the non-earning partner to contribute in other ways, and for both sides to be OK with this, and for the non-earning partner to be considerate and appreciative of the fact the earning partner is contributing the time and effort that the money represents to the relationship.