Its easy...I dont explain. It is none of their business. My friends and family know if they ask but as for others it really never comes up in conversation.
When it does come up in conversation to someone who simply doesnt have a "need to know" I simply state the truth "I do alright."
That is the truth, I make pathetic awful money but I am good with money and so is my wife who has a great job and I do alright. But my friends who do know get a kick out of it when I name professions who make more than me to include taxi drivers, 7 eleven clerks, full time mcdonalds employees, school bus drivers and the list goes on.