My wife is looking forward to when #bitcoin hits $100k so that we can take some profit and upgrade our lifestyle. Not sure how she will react when I tell her that we’ll never sell for fiat.
Discussion
Better go ahead and tell her you lost the keys
You have the window of opportunity to provide clarity on this matter beforehand. 
She didn't ask you to sell for fiat, but sell for housing, cars, expensive clothes, restaurants, holidays,...
You should better explain differently. "Do you prefer some expensive stuff now for the next few months or in ten years for the rest of our life?"
This should convince her, then you have extra time to plan and convince her she doesn't need these stuff.