season 2, it seemed like the groundwork was being laid for just such a romance to blossom.
In season 2, episode 4, "Redanian Intelligence," Triss does make a , asking Geralt to come to bed with her. Despite expressing that he clearly cares for her, Geralt turns Triss down, seemingly because he thinks she is too good for him. He ends up reconnecting with Yennefer later on in season 2, and the brief spark of romantic subplot between Geralt and Triss appears to be extinguished.
The most likely reason that the show kills the love triangle is that the plot has come to rely heavily on Yennefer and Geralt's relationship. In addition to providing some of the most continuous conflict in season 1, their tumultuous romance continues to serve as a primary motivator for both Geralt and Yennefer in The Witcher season 2, and seems integral not only to their character development, but also to Ciri's. That being said, it is still possible that a romance will develop with Triss later on, creating even more conflict in the already precarious relationship.
Geralt's relationship with Yennefer has been essential to a number of major plot points since season 1. Her desire to have a child inspires him to seek out Ciri, and Yennefer's affection for Geralt also contributes to her decision not to betray Ciri to the Deathless Mother at the broken monolith. Yennefer develops an attachment to Ciri who is basically Geralt's adopted daughter, and the end of The Witcher season 2 suggests Yennefer will continue to help protect and train Ciri. With the plot now relying so heavily on Yennefer's involvement with Ciri and Geralt, it's hard to imagine that their romantic relationship will simply be forgotten.
There is, however, still hope for a love triangle to evolve with Triss. While Geralt and Yennefer appear to make amends at the end of season 2, they've also spent the vast majority of their relationship in dishonesty, first with Geralt making a wish to keep Yennefer in his life, and then with Yennifer almost sacrificing Ciri to the Deathless Mother. They don't really have a strong foundation on which to build a relationship, and Triss has proven to be something of an antithesis to Yennefer's personality. She is gentle, understanding, and nurturing to Ciri, and Triss' role in The Witcher season 2 has focused on her insistence that Witchers do have feelings. Particularly if Yennefer and Geralt clash again, their fractured romance could drive the Witcher straight into Triss' gentler arms.
There are clear reasons to do away with the love triangle in The Witcher especially as it pertains to the plot. While such a storyline works well for a video game, giving the player a choice of who Geralt romanticizes, but the trope has become somewhat played out for television. Regardless of who viewers would prefer to see Geralt end up with, only time will tell if there will ever be romance between him and Triss in The Witcher season 3 and onwards.