The wife and I have a similar arrangement. She's addicted to perfume oils manufactured by Black Phoenix Alchemy Lab and spends just as much on purchasing those (along with her fancy soaps from a variety of sources) as I do on kilt items and homebrew supplies. So long as it comes out of her "allowance", I don't have a say, just like she has no say in how I spend my money. Of course, that doesn't mean she can't tell me that I bought something ugly.

There are times, however, when there's some special limited edition that she'd like to have, or some really cool sgian dubh I come across, that we clear the order with the other, but that's become few and far between, and then we budget it into monthly budget somehow, which usually doesn't take much finangling as I (conservatively) budget every dollar that goes out.

It's the only way my left brain will let me be happy ;)