The Duke's Darling Daughter-in-Law

I possessed the body of the no. 1 villainess, Ellie, who was a terrible person who tormented the male lead in the orphanage. I quietly waited until the day that the duke would pick him up vowed to never get caught up in the novel, so she would not see the ugly ending that the villainess did, until... "I will also adopt the child next to him too... She will become my daughter-in-law" I was adopted along with the male lead! I can't just do this? There's a separate heroine!