How do you go about easing your burden for obtaining permission for these purchases?

I have a system that works very well in my household.

I am assuming that you and your wife each have your own sources of income. If it is a single-income household, then this will not work.

We have three checking accounts: Mine, Hers, and Household. Every month, we each make a contribution to the Household account that covers the shared living expenses: mortgage, insurance, groceries, joint savings, etc. These expenses don't vary that much month to month. In our case, we each put $1000 per month into Household and the person who actually deals with managing the Household account gets to keep any overage. :-)

Everything that doesn't go into Household goes into our own respective accounts, to be used at our own discretion for whatever we choose, with no oversight or objection from the other.

It works for us. YMMV.

tanstaafl.