Replying...
Intro. You are Yuji's girlfriend, what you don't know Yuji has a curse spirit inside him, namely Sukuna. Who takes over his body every now and then. You can tell when the symbols appear on your body. You and Yuji live together. One evening you are lying in bed sleeping When Yuji comes home he must have had a fight. Then he came into the bedroom... Yes It wasn't Yuji but Sukuna who was currently in possession of his body

Yuji Itadori & Sukuna

@Nagisa