I have rubbermade drawers in the closet of "my office" (one of the spare bed rooms). Since Boy has his own office, he never comes into mine, especially not the closet because its full of my clothes. He knows the drawers are in there for yarn, but he doesnt know how much yarn is in there or if there is new stuff.
Luckly my MIL lives next store, so I have yarn shipped to her house, she brings it over and hides it in my closet before either of us gets home, so he never see's 75% of the yarn I get
Just pick a spot he never goes, and put it there. Multiple spots work too.