(1) He is married to Barbara Segaas.
They got married
(2) He is married to Jacomijn Hamelinck.
Permission for the marriage has been obtained in Ossenisse on December 21, 1667.Source 1
They got married on February 19, 1668 at Ossenisse.Source 1otr. 21 dec 1667; tr. 19 feb 1668; bdg. Guiljam Stommelingh wed[uwnaar] van zal[ige]r Barbara Segaas woont tot Moerbeeck; br. Jaquemijn Hamelinx jd woont op Ossenisse; opm. getuijghen Jan Stommelinck, Jan Everaarts, Adriaan van Ackeren, Lijsbeth van Rossum; den 15 januarij 1668 heeft inspraake gedaan Pieter Segers jm van Ossenisse dogh is in der minne bijgelecht en sijn deselve getrout op den 19 februarij 1668
Ossenisse ondertrouw 1648-1682 https://www.geneaknowhow.net/script/zee/Ossenisse_ondertrouw_1648-1682.pdf