The Sims 4 latest patch notes open the doors to polyamorous relationships and a life free of jealousy

pcgamer.com:

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