In a dev diary written by SimGuruJessica, the design lead on the upcoming The Sims 4 High School Years Expansion Pack is the announcement of a free update coming to the base game along with the expansion. The update will bring changes to sexual orientation within The Sims 4.
Players will be able to choose from a few options in the Create-A-Sim (CAS) section, including whether they are romantically attracted to men, women, both or no-one at all. They will also be able to choose whether they are "exploring" romantically, allowing Sims' sexualities to be more fluid and potentially change throughout gameplay. Finally there is an option for the types of Sims you're open to "mess around" with, again, men, women, both or neither.
You can read some more in-depth information about the update here, including on how aromantic Sims will work, why there are still only two genders, and where to find the new updated options in the game.
For those wondering whether this option will be able to be toggled off, SimGuruJessica words it perfectly:
"No. While we try to give players the option to toggle certain gameplay features, LGBTQIA+ identities are a fact of life and not a toggle to be switched on and off."
The new sexual orientation update is thought to be coming to the base game along with the High School Years expansion on 28th July, 2022.