This mod adds new relationship type, love triangles, to The Sims 4.
In CAS give your teen Sim the Torn Between Lovers trait located in the Emotional category.
This trait will unlock a new social menu and interactions.
Romantic Teen menu
The romantic teen social interactions will build the romance level up. Once you are “Romantic Interests” with the target teen you’ll be able to create a love triangle.
Check the relationship panel to make sure what the relationship status is. Create A Love Triangle will only appear for Romantic Interest relationships.
Now you can do the same with another Sim and complete the love triangle.
When you add a teen into your love triangle a new social menu and interactions unlocks.
The love triangle interactions are mostly mean and mischief. If you don’t want to ruin the relationship you can avoid using them.
From the Love Triangle menu you can End a love triangle with one of the love interests or both.
You can also decide which Sim you ultimately want to be with by using the I Want To Be With You interaction. This interaction will add the Teen Lovers relationship bit.