My business partner keeps buying things without asking me

I started a small manufacturing business with my best friend from college close to two years ago. 50/50 partners. Everything was great until about six months ago or so. We have a shared business account but we both also use our personal cards for business stuff pretty regularly cuz if you're at home depot or whatever it's very normal to use whatever card is in your wallet. The problem is that he's just TERRIBLE about telling me what he bought or sending receipts. Last month I'm going through o...