Shared Instagram problems

My fiancé and I were off social media for a couple years, so we recently made a shared Instagram for various reasons (He isn't good with social media, didn't want his own). We decided to have Instagram for just friends from when we were in school and Facebook for family and family friends and keep the 2 totally separate. Now, he's accepting requests from family and family friends on Instagram (where we post things that are more geared towards the audience we had in mind) and keeps doing it even after I ask him not to, since that is what we agreed upon. Idk what to do.