I'm gonna have to turn in my manliness card for this, but my suggestion to you is to think beyond the things you can buy for him or cook for him. There's a book called "The Five Love Languages". I'm guessing that yours is "receiving gifts", so that is where you are going with a 12 days theme.

But there is also "words of affirmation", "quality time", "acts of service" and "physical touch". The key is to learn which one or two of these things are most important to him and direct your actions appropriately.

http://www.fivelovelanguages.com/learn.html

Good luck.