I'm looking for a manga that is about a guy having a crush on his friend who is nice but t...

I'm looking for a manga that is about a guy having a crush on his friend who is nice but turns out the guy is only nice at school and rude at home then those two date then always after they have sex the other one leaves to take a shower and not to lay down and sleep together so what is it called I am pretty sure it is a side story on a manga it is I think like a wolf in sheep's clothing thing please somebody I have been looking over 2 months for it please someone help