If you want harmony in the house, listen to your wife and try to work with her. Even if you disagree. As for selling the New Englander and such.. If I were limited to three rifles, it would be a hard decision as to which ones stayed in the stables.
Now she did say rifles.. So remember, with a Renegade or Hawkins, you can get Green Mountain Barrel and make different rifles out of them. They come in Flintlock as well. Then you have three rifles and several barrels.. still in the rules book as legal, but opens your options. Or you can just buy as many guns as you want and sneak them into the house and hide them all over the place.
In my case I bought them when I wanted and never asked. My ex never really cared as long as it made me happy. And it would not have mattered anyway...