That’s why the phrase ends not with “I was wrong” or “I apologize,” but with

Frequently leaves home under the guise of "business trips" to attend sokubaikai (doujinshi sales events like Comiket) without his wife's knowledge.

Translated, this roughly means: "It's not good to go to an outside place without telling your wife, better not to."

A humorous take on a husband trying to hide his "otaku" purchases (merchandise, books) from a strict wife, only to be caught in increasingly ridiculous ways.