Oh there is a fine art to it. Always pay in cash (credit card statements will get you every time). Always stash the receipts where she wont find them... If she does catch you spending money, act like you are so upset that you have to keep spending money on this bike - like you feel like you bought a lemon and are now being taken to the cleaners. Had my wife thinking I was so upset that I had to fork over a bunch of money for Mavic wheels.
