Solved
Finishing the Marriage Quest
Trying to get two Sims married but didn't finish the quest and now I can't do anything involving marriage. Did I need to finish it for them to get married and is there any way I can try it again?
Yes, you need to complete the wedding quest to unlock marriage in the game.
The quest will restart as soon as you complete a Proposal event between two Sims.
Here you can find the Wedding Quest Walkthrough by @Phantomlover1717
https://answers.ea.com/t5/General-Discussion-Feedback/Wedding-Quest-walkthrough/td-p/7399492
