My SO failed....

I borrowed a Zofran from my mother. Then I got my own prescription for it. The other day I come home and he says "Your mom stopped by and wanted a Zofran so I told her where your pills were." UMM WHAT!? I don't tell my mom where my pills are because shes a pill popper and will take full advantage of coming and just taking what she wants out of my pills. I had 20 pills and now I have 7. Im soo mad at him but he thought I was being silly because I took one of hers and he thought she would only take one of mine.