FWIW, I still am not getting the "Game of Thrones" vibe from Narek and Narissa. Narissa is clearly "flirting" with her brother, but he seems totally disgusted by her doing so. Still not sure what is going on, but I'm pretty sure it's not that he no longer has the hots for his sister after falling for Soji.
For all, we know incest could be tolerated in Romulan culture.