@crinrict I started a completely new game, made a new family with four people and stuck them in a small house (in a Willow Creek, while my other save family is in Evergreen Harbor). I cheated them all to 100% friendship, but then paired them off and stuck two outside, two inside (so there wouldn't be any accidental crossover interactions) and spammed romance until each couple had a full romance bar, asked to be bf/gf, first kisses/woohoo done, etc. I had all four of them watch a romance movie so they would all be flirty, then turned high speed on and let them make their own choices. They moved to sit around the table and have a four way conversation and within about 20 game minutes, one member of couple B decided to flirt with one member of couple A. The only difference was the significant others in this family got sad instead of angry.
I did some more searching, and it seems like the update that added the loyal trait that changed all the mean interactions so some people are experiencing sims being mean to each other all the time also changed all the romance interactions. Most people are talking about the mean sims, but a few others are having the romance problem. In adding the Loyal trait, it sims like they decided to make every other sim in the game a very disloyal cheating * and it makes the game pretty much unplayable.
