Sonna no Koi Janai

Just as the title says, the stories in this book are centered on pointing out all the things "that's not love". Story 4 involves a girl named Mami who initially believes that her relationship with her longtime boyfriend has gotten boring. To make matters worse, this cute guy at her workplace kissed her out of the blue one afternoon, which got her questioning her "love" for her boyfriend even more. So the classic thing happens...they break up. But is that all there is to it? She didn't love him, right?