Question juridique clé
Whether the spouses' main tax domicile for 1999 was in Zurich or Thurgau.
Solution extraite
The spouses' center of life in 1999 was in Winterthur, so their common main tax domicile was in Zurich.
Motifs extraits
The husband lived with his family in Winterthur and commuted daily to Frauenfeld; the Thurgau apartment was retained only because of the residence requirement. A residence requirement in the work canton cannot override the family domicile.