One of the new base game features in The Sims 4 called Romantic Boundaries is attempting to mimic real relationships that are "nuanced and complex" by letting players tweak their Sims' preferences around exclusivity and jealousy.
Arriving in the upcoming Lovestruck expansion. "[You can] define the conditions under which your Sims become jealous," according to the patch notes. "These live in Create-A-Sim alongside the Gender and Sexual Orientation options in the Identity Panel, and you can change them at any point in time."
There are different levels of jealousy that you can assign to Sims now: getting jealous at non-physical romance, physical romance, "WooHoo", or if you don't want to have to deal with all that emotional mess, you can change it so that they won't get jealous at all. Although this isn't default, so you'll have to change it for everyone you want to be involved with, otherwise, you'll likely jump headfirst into some serious relationship drama. If you want to go about things through gameplay, the new update also allows Sims to change their opinions about their romantic boundaries through conversations with other Sims.
While polyamory may not be for everyone, it sounds like this update will be a great help for those who want the trait for their Sims or those who just don't want to choose between partners.
"FINALLY! I am tired of giving all my poly sims the player trait as a workaround!" one player says in a Reddit thread. Before this recent patch, you couldn't officially create polyamorous couples in The Sims 4; the only way players could get around it would be to complete the serial romantic aspiration to get a trait that prevents it. Or you could copy paste a cheat that would automatically give them said trait without having to do any of the work.
But if the polyamory works out too well then there's also an option to hide relationships in the Relationship Panel. "You can remove those Sims (who are not members of your household)," the patch notes say, in case your Sim's got way too many lovers and crushes to scroll through.
This new base game feature will also help fix a couple of frustrating bugs that were making Sims jealous for absolutely no reason at all. "Some of my other sims constantly lose relationships because they think it's cheating if their partners are out in public," another player says. "I think strong reactions with smarter AI would be good though."
The new update will also add a quicker and easier way to select outfits by simply adding an "apply all" button for your Sim's accessories, hairstyles and makeup. You can see how it'll work in the recent developer livestream.