Your manner of thinking is all wrong. What you should NOT be asking yourself is "I wonder how long it will be before she finds out". We all know that she IS going to find out. What you should instead be asking yourself is "What lie am I going to tell when she finds out". Well, Tweak, thats what were here for. First, you go and tell her what you did. I know, I know, your thinking.."Are you *&#^#* crazy!?!?" The truth of the matter is, well...yes a little bit. Sometimes we have to be to survive. This is how it's going to play out. Bear with me here.
Go to her, with Neptune in hand. State your dominance with a strong, bold voice--"Marvel at what I have sculpted, woman. It is Neptune. God of the mighty sea. It is a tribute to him so that the plague of darkness will not fall upon us or our family."
This statement will obviously startle her. A question will obviously ensue. "..what are you talking about?"
"I (insert name here), man of one less rib, have saved our family and many other families by paying homage to Neptune by creating his likeness from our cheese board."
Now she will most likely get a scowl look on her face and start looking for the ill fated cheese board, all the while torturing your ears with words of scorn and pain to be paid.
This is where your creative talents will really come into play.
Assert your alpha-male qualities with a swift smack of your hand on a solid surface, so as to make a loud startling sound.
"Evil woman, everybody knows that cheese cut on a wooden board gets into the fibers of the wood. Then said cheese will fester with mildew and other microscopic bio-hazardous life forms. Cheese draws mice like a moth to a flame. The mice alone are not a threat, as they have built up an immunity to such hazards, but the fleas that feaster upon the mice feed upon the blood of the mice that have fed on the bio-hazardous fungi infested cheese board fibers. The tainted blood then mutates inside the flea as the dreaded "black plague". Mouse infested ships traverse the oceans, trespassing upon the mighty Neptune, spreading the disease worldwide. Millions would surly perish upon Neptune's wrath if not for our sacrifices."
This should definitely get you into the clear. I would go so far as to say you will get to place this plaque anywhere of your choosing without repercussion. Front door, above the bed, on the ceiling, wherever.
If any more problems arise, just call Arts support staff. $1/minute-5 minute minimum. If you make many projects from household items, you might opt for the silver or gold support packages. Your welcome.