Very sensible and my wife and I have a similar arrangement. In reality though what this arrangement means is that she doesn't get me anything for Christmas, birthday or valentines day but she proper sees her arse if I don't get her anything. Clearly I am the most amateur of all amateurs.
We have it the opposite way around.
She always gets me something because she enjoys shopping with her mates, but doesn't expect anything in return because of our arrangement.
Living the dream lads.