In The Sims 2, the wedding arch is used by selecting a member of the engaged couple, clicking on the the arch, and selecting "Get Married" or "Join Union". While Sims can get married or enter a Joined Union with or without using the arch, using the arch allows a player to add a bit of formality, as Sims who get married or joined under the arch will change into their formal clothes. If the relationship between the two Sims is too low, one may call off the wedding. While this can happen regardless of whether the arch is used, it's more dramatic if the arch is involved.