When my boyfriend uses my stuff he should let me know.
What kind of stuff are you talking about?
Any kind of stuff. Milk, paper towels, shampoo.
It's not reasonable to expect your partner to tell you whenever they do something or use something. You shouldn't force your boyfriend to tell you every time he uses shampoo, because he'll probably get extremely annoyed by it.
I'm thinking about telling my boyfriend that he didn't tell me every time he used stuff.
Maybe you should only worry about him telling you if he has finished your stuff. It would probably be annoying for you both if he has to tell you every time he uses your shampoo or a paper towel.