I just can't imagine asking my wife if I can buy anything. I mean, not because her opinion is of no consequence, but because we each do what the hell we want with our money. We each contribute to an account that we don't really have to add much if any to each month that covers our living stuff, which is fed by investments that each have control of, so pretty much our money is our money.
If most people living month to month would just set down with a finical planner, they can get past that impoverished shit. You do not have to be rich to start letting your money work for you. I know, I've been there with my thinking, but you do not have to live in that situation. A few years of tight bootstraps, proper planning, and soon you won't have to live in that month to month bullshit.
Then, you buy what you want, and she can buy whatever her heart desires.