budgeting in two currencies: the perfectionist's nightmare

The fact that Julie and I are both detail-oriented people means that tracking our expenses is a relatively conflict-free part of our marriage–we both agree on the need for accuracy in maintaining a budget. The fact that I love Microsoft Excel makes record-keeping fairly uncomplicated*. But the fact that we both tend towards perfectionism makes budgeting in two different currencies really irritating. The constantly shifting exchange rate** between the Nicaraguan córdoba (C$) and the US dollar means that complete accuracy is virtually unattainable. Discerning the absolute value of money starts to feel like a philosophical question.