The process for people with spouses who just don't/won't understand :
1. wait at the door for delivery man to make sure he doesn't ring the bell (pretend you are cleaning the porch or trimming the bushes or putting the bins out).
2. take the box to your room/study/basement immediately.
3. carefully dispose of the cardboard box and hide the manufacturers box in the loft
4. test your new lens/camera carefully making sure you aren't over excited around them. Just pretend you are just playing with your toys as usual almost like "oiling" them.
5. sell your lens/camera if needed down to a level where she/he won't notice the difference.
6. Repeat the process.
Don't you know I still own a Sony A57 with sigma 18-250mm lens.