I have the game and i can enlighten you as to what is going on yes?
Fate, her name, did catch the guy, Jaku, in bed with Norma during Norma's story arc. When it comes to Fate's, she keeps avoiding him as he chases her about wondering what's going on. Eventually he catches her in her room and she cries out how she had feelings for him and seeing him with Norma made her upset. Well, you can guess what happens after this anyway.