"Just buy something and I'll get the kids to wrap it and tell them I bought it"

[ThisUsernameIsAvailable]

That's a fucking cop out isn't it?

I get to buy my own because he doesn't know what I want.
I've told him and shown him many things I want..

So, Aibu to buy my new tattoo with 'his' money (finances are joint really) and tell the kids that's what they bought me for Christmas?

sounds like a plan. Maybe get them to help you choose or design it?

Misery - him, not you!

Go for it on the tattoo, but try and get the kids somehow involved rather than just turning up with it afterwards, that wat they still have the anticipation / excitement of you opening it. Does you artist do gift vouchers? Or could they design a gift voucher on his / her behalf that could go in a card for you after you DH has put the deposit down?