If you have a nice, simple Base Game wedding, your Sims will change into some random wedding outfit for the occasion.
Bethrothed Outfits adds more random outfit choices for Base Game Weddings.
Betrothed Outfits is a modular mod, but you can mix and match the modules however you like (even though I do strongly recommend using at least the Base Game version).
This is the High School Years Addon. It adds more wedding attire that came with that pack to be available as random Base Game wedding outfits.
Required Packs: High School Years
Compatiblity: Will conflict with any mod that alters these tuning files:
default overrides of the clothing I tagged to be available for this mod.
Note: EA CAS content that has been assigned for use with this mod will be seen as CC by the game. If you want to create a Sim to share in the gallery, temporarily delete the mod. You can also save already existing Sims anew after deleting the mod. They will then show as CC-free.
Creator website: https://www.seebee.de/sims4me/