He needs to learn how to control his anger or frustration better. Why can't he listen to you or care about how this effects you? That says a lot about him. He is not respecting your wishes enough to curb his behavior. I would tell him he has an anger issue and that you will not accept him slamming the toilet seat down every time he gets frustrated with it. Draw the line and your boundaries of what is unacceptable and acceptable for you.