NAH but I wonder if it’s less about the secret for her and more about feeling like it’s not really her home. When my partner moved into my apartment, it was definitely tough for her to feel like it was equally her living space because I owned it, all the furniture was mine, most of the decorations, etc. We got some furniture and decorations together, which helped, but it was definitely something she struggled with for almost a year. If she found out 8 months in that there was a secret room she never heard about, I’m sure that would have made it feel even less like her equal home/space. It might be worth talking to her about whats causing her reaction at the root.