I have no need to hide anything from the wife, she is quite understanding and all the bills get paid every month.
Normally I will mentioning to the wife either I'm thinking about, or have bought whatever it may be. Although with more expensive purchases I tend to do a sense check and discuss it with her first as she will have some valid points against my logic
Although I earn every penny that comes into our house, It is our money.
If I want something then I'll buy it, on the same token she is free to buy what she wants too (Although typically she'll ask first, and it's very rare I'll say no)
This way keeps us both happy
and prevents any arguments etc.
As has been said a number of times above, if you are having to hide your purchases from the partner then there is something wrong somewhere.
The only purchases I hide are Xmas / Birthday and Surprise presents.
Happy purchasing