(since the price is continuing to plunge) My wife thought its a waste of money and a bad investment - "See! I told you, you didnt listen to me!" Im gonna be stubborn and still HLOD! My gut feeling its gonna spike in few months and hopefully, my wife is WRONG and start smiling when she sees the price going up and strong! 
You have nothing to prove to her if you use your own money. If you used shared funds (like groceries money) she has a point - then there needs to be consensus a priori - not in hindsight. And of course there needs to be due care when handling those funds.
Oddly enough people like that tend to be unsupportive in tough times, but want to enjoy the good times. To those I say:
"If youre absent during my struggle, dont expect to be present during my success." - Will Smith