Re: Sims mobile wedding event
You can't throw a wedding party until after you are married.
You need to get married first.
There is an alternative way to do it through the wedding quest, but I usually do it this way:
1) Have you started a flirty relationship with the sim you want to marry?
2) Have you progressed that story far enough to get the propose activity?
3) Have you finished the propose activity?
4) Have you purchased and placed the wedding arch, Floral Pillar and Rose Lattice? (purchase them in the home collections section, not the party. section)
5) Once you have done these things click on the wedding arch.