Feferi always had a matesprit crush on Sollux, but she never tried anything because his flushed quadrant was filled with Aradia. She stayed silent all about her feelings, only daydreams the closest she thought that she would get to being with Sollux like that.
When Aradia died, Feferi tried to help him, but the Captor closed himself off from everyone. She still tried though, and she was able to help a bit. Feferi wondered multiple times if Sollux could actually have flushed feelings for her now.
She learned how he felt much later, when the game that they were destined to play. There, Sollux was able to tell Feferi about how he felt about her. Feferi and him quickly became matesprits, and they spent so much time together.
Hours upon hours were spent between the two, and Feferi was really glad that Sollux actually listened to her. It was pleasant but also not pleasant at the same time. She had someone who helped her and listened to her, yet he wasn't actually seeing her.
She really tried though. Feferi really tried to be just herself, but as she tried and tried, she saw herself more and more as Aradia. It soon became her paranoia, and she couldn't handle it anymore. Feferi hid from everyone, especially Sollux.
Sollux tried to get to her, really worried for her. She wouldn't show herself to him, paranoid that he would never see her for herself. Actually after days of trying to get to Feferi, the mage was able to see her. She wasn't herself, but all that crossed Sollux's mind was to hug her. He didn't care about what she might do to him, he didn't care even if she stabbed him, he just wanted hugged her.
Feferi was caught off guard when Sollux actually hugged her. She just sat in his arms for a few minutes as he just rubbed her back gently. When she pulled out of her surprised gaze, she hugged him back, crying. Sollux whispered in her ear how much he loved her, which made her cry more. He comforted her, and after a few hours she was able to learn that Sollux Captor sees Feferi Peixes as Feferi Peixes, not Aradia Megido.