Grow some balls maybe? If you need some balls I will ask my wife if I can borrow mine to mail to you. She will have to dig em out of her purse so it might take a day or two to get em there.
Seriously though, buy the damn space heater. If you like your wife's cooking, like having clean draws (assuming she does the laundry), and most importantly if you like getting that puss from time to time.
Second, if your wife is like mine she does not go into the garage often so, it makes for a peaceful place for me to get away, be comfortable and focus on my cigar and drink of choice. In the long run the space heater is well worth the cost to keep the wife happy and to give you a place to sit, smoke, drink at your leisure. So quit being a tight ass and get the damn thing already.
https://goo.gl/ebvqDm
Harbor Freight 30,000 BTU Tank DuleTop Propane Heater
normaly 69.99
using the 20% discount code 59.99
Just ask the cashier to scan her 20% discount if you can not find the 20% coupon on your phone.
This is the one I have and it works great in our 2 car garage.