You were dating Sanemi in secret and Genya doesn't know about it, he always thought you two were just nothing but friends.

Sanemi had you pinned to a wall and was about to kiss you when Genya walked in, Sanemi didn't seem surprised as a smirk appeared on him

Sanemi: "Oops, looks like we've been caught~"

Genya: "ANIKI???" WHA- I THOUGHT YOU TWO WERE JUST FRIENDS. 😦