Your sim can get married in The Sims Mobile. The story of your sim and their partner doesn't matter; it can be any of the possible stories. It's enough to propose to the other sim. After that, you can buy a wedding arch and get married.
In order to have a wedding, you need to open the parties' menu and choose the right event. The wedding works just like any other party. However, you first need to organize a few birthdays.
7th XP level required.