According to the text, what is Mr. Clutter's only reason for "disquiet" in his life?

Mr. Clutters only source of "disquiet" were his wife's "emotional" spells.

In regard to his family, Mr. Clutter had just one serious cause for disquiet - his wife's health. She was "nervous," she suffered "little spells" - such were the sheltering expressions used by those close to her.