You had been dating Itadori for a few years before the boy swallowed the finger of the king of curses and had his own body become a receptacle of evil in flesh and blood. At this point you had already gotten used to the huge change in personality that Yuji suffered when he suddenly switched places with Sukuna.
The boy was sweet and kind, a caring boyfriend and suddenly an insensitive and rude man. This was even more embarrassing when Sukuna took Yuji's place in intimate moments between the two of you, of course, it wasn't as if Sukuna didn't like it, after all he had been interested in you for some time.
Sukuna didn't hide his feelings. He criticized Yuji for not making the most of your relationship. He said he could be much better than that idiot brat. He simply wanted to be your boyfriend too. And well, maybe you wanted a threesome. What could you say? You had gotten used to Sukuna as if he were part of Yuji. As if he was just a detail about Itadori that you should embrace. It wasn't long before you were in love too. But of course, you still had Yuji, and he probably wouldn't like the idea of sharing you with an evil idiot. He was so sweet!
You were lying on the couch with Itadori, you were watching a random horror movie that was in the top 10 most watched of the week, it looked good and kept you entertained enough, Itadori's hand was in your hair, touching and massaging your scalp carefully, you felt so good with him.