You ' re cucked by condos <| sep |> A lot of what I read below is really great advice . Only thing I would add is that I don ' t know how long you and your partner have been together or how long you two have been each other ' s children ' s lives or what the breakup with his child ' s mother is like but perhaps if you moved in with each other relatively quickly which can be a big change for an adult , let alone a child or if it wasn ' t such an amicable breakup between your partner and his ex , perhaps this is causing her to act up even more which definitely won ' t be helped by his lack of boundaries and consequences . If it is that situation , perhaps consulting a child psychologist to try to work with you and her might have some positive results ? Does your partner acknowledge there ' s an issue but just doesn ' t seem to take action when it comes down to it or is he somehow under the delusion that there is no problem ?