Marriage certificates of civil status only become public after 75 years. Also don't forget to check the marital attachments, Open Archives often provides links to this. Civil status records are always drawn up in duplicate: one goes to the municipality where the event took place and ends in the municipal or regional archive, the other goes through the court to the provincial archive (RHC).
This index contains 28,465,655 historical person listings.
The marriage certificates as made available online by North Holland Archives, Brabant Historical Information Centre, Gelders Archive, AlleFriezen, Historical Center Overijssel, City Archives Rotterdam, AlleGroningers, Regional Historic Center Limburg, The Utrecht Archives, Zeeland Archives, Municipal archive The Hague, Regional Archives Dordrecht, Drenthe Archive, National Archives / Archives South Holland, Regional Archive Tilburg, West-Brabant Archive, Heritage Leiden and environs, Regional Historic Centre Eindhoven, Regional Archive Langstraat Heusden Altena, City archive Breda, Archive Delft, RHC Rijnstreek en Lopikerwaard, Regional archive Voorne-Putten, Regional Archives Rivierenland, City Archives Enschede, Municipal archive Schouwen-Duiveland, Historical Archive Westland, Municipal archives of Venlo, Municipal Archive Borsele, Municipal archive Venray, Regional Archive Alkmaar, Municipal archive Schiedam, Regional History Center Vecht and Venen, Rijckheyt, center for regional history, Municipality archive Alphen aan den Rijn, Hof van Twente municipality, The Flevolands Archive, City archive Zoetermeer, Municipal archive Ede, Municipal Archive Kerkrade, Municipal archive Hengelo, Municipality of Zederik, City of Lommel - Archive service, Municipal archive Wassenaar, Municipal archive Zaanstad, State Archives of Belgium (Antwerp-Beveren), Municipality of Oldenzaal, State Archives Belgium (Hasselt), Municipal Archive Ommen-Hardenberg, National Archives Suriname, Historic Centre Leeuwarden, Eemland Archive can be searched here.