Harvey,
Your new Sebenza is indeed an occasion for celebration and I think that most of us share memories of the exquisite agony of the wait for its arrival.
As to your wife's reaction to its cost, look upon it as a rare opportunity for creativity. Explain to her that you have not made an outrageously large expenditure for a knife, but, rather, you have taken advantage of a once in a lifetime opportunity to invest in a true marvel. You have not just purchased a fine knife, but one that will also transcend our normal understanding of the physical world and eventually, though inanimate, grow in size. Then, at later date, when you take delivery of your new large, left handed Sebenza you can show it to her as proof and thus explain away and justify the purchase of both. The only real problem with this scheme will be in continuing to carry and use the small without her knowledge. I am sure that you will find a way around such small details.
Be sure and let us have your opinions when it finally arrives.