(1) He is married to Trijntje de Jong.
They got married on May 16, 1906 at Leeuwarden (Fr), he was 23 years old.Source 3
(2) He is married to Tjitske Douma.
They got married on November 29, 1913 at Achtkarspelen (Fr), he was 31 years old.Source 4
Geboorteregister 1882, Westdongeradeel
http://www.graftombe.nl/names/info/538088/smits
Huwelijksregister 1906, Leeuwarden
Huwelijksregister 1913, Achtkarspelen