Question : Should my advisor know if I am auditing unrelated courses?

Motivation : I am a PhD student in Computer Science and at times, I wish to audit courses which are not at all related to my thesis or research.

For instance:

* For Fun : Italian Food and Art
* For probable post-PhD jobs (but not related to thesis) - Econometrics, Quantitative Finance.

In general, my advisor is cool and won't mind the hour(s) I spend in the classroom. He allows me to work from home or wherever and doesn't care about "seeing" me in my office so long as I keep doing my work on time (which I do). 

If I tell him about the courses, he unnecessarily might get freaked or worried and might question my intentions (which I can obviously clarify), If I don't it seems as if I am keeping something important from him.