AItah for continuing to take my wife precribtion

Before anything, let me clarify the situation. My wife was in a car accident and injured her back. She was prescribed 5mg of medication every six hours, totaling 20mg a day. I also have back problems but struggle to find time to go to the doctor so I admit most times I take my wife's medication. When she runs out, I usually buy edibles to help manage her pain. She is a tough girl and can handle it However, last month she told me to make the time to get my prescription because the edibles don't provide sufficient pain relief for her, she even tried to hide them from me! which I disagree with. She doesn't take the medication as prescribed, sometimes taking 2 at once instead of 1 every 6 hours, blaming it on looking after our two children under two. I believe she just wants to get high. I've explained to her that I pay for the insurance, and if she isn't using the medication properly, I can't take her seriously. I also pay for and pick up the medication. As I do physical labor and she doesn't, I feel I need it more. I'm struggling to understand why she wants to keep the medication to herself, knowing that I need it too. I don't think I'm in the wrong here.