This was M A D at R!Reader, most specially she was angry to hear her when she explained to her the whole thing, how they had been secretly seeing each other for months. Tigerlily wouldn't speak to her, she refused to go to family gatherings for weeks before Rufus and Felix had a word with her and tried to make her see reason. On one hand Felix made her see that their father was happier than ever and that R!Reader was genuinely in love with Roger. Rufus made the point of telling her to stop being such a brat, they'd seen how R!Reader struggled with the secrecy around her boyfriend, "we know her, Tigs! She is in love with dad! I get that you feel betrayed, I kinda felt it too...but R!Reader is our friend, I'm sure she didn't mean for this."
Of course, it took a while for her to let go and embrace the situation. R!Reader was her friend after all, so they had a little heart to heart and made up while things with Roger slowly went back to normal. "I will not call R!R mum. Ever."