My Childhood Friend Who Is My Girlfriend Is Not Looking at Me

My childhood friend and lover, Kana. She no longer has any interest in me. Even though she is very friendly and cheerful to her other friends in class, but when I talk to her, she only responds me with a single word, ‘Hmm.’ While I feel I’m just being used by Kana as a convenient partner, Setsuna, my senior who is the student council president, urges me to break up with Kana. I refuse her offer at first, but Setsuna tells me that I should make Kana feel threatened of losing me by going out with her.