Once, I went against what my husband told me to do, and his predicted outcome was the result. Not only was he right, but if I had listened in the first place... Then, I went out of my way to fix it without him knowing... Horrible! Then, I lasted about a minute before I confessed what I had done. He...... laughed.
Respect him enough to tell him the truth. Sell the dumb thing on Ebay, and do it right the next time. You'll end up better off in the long run.