Hi Dee, I see two things that you might need to do differently to get that extra border you want:
1- once you have selected the frame, don’t invert the selection. What you want is similar to making a sticker, so keep the selection of the frame and expand directly.
2- before #1, you should make sure there is some space on the edge of the frame to accommodate that expanded selection. I am not sure if the image you posted is the exact edge of your image or not, but just make sure you have plenty of room.
Hope this helps.