I think her brother knew that they were all there watching. Which is why, in chap 95 (I’ll add the link)- he says “I’ll show you” and then he kissed ruby.
And he kisses her to, ig, shock the ppl watching so they would tell Ize and then he’d get upset with Ruby. Bc, bro wants Ize to “discard” Ruby.
https://mangaextreme.com/manga/how-to-get-my-husband-on-my-side/chapter-96











In these stories the alpha always wins