He is married to Commertje Betsmansdr..
They were married in church on July 17, 1611 at Oude Tonge.Source 1
Julius
Den 17 hebben sich inden huwelijcken staet begeven JanClaes, jonckman uijt Sommeldick, met Commertgie Betsmans, jonge dochter uijt Doude Tonge, getuijgen des brudegoms Willem Betsmansz ende Pouwels Claesen, des bruijts Neltgen Cornelis met Maijken Claes