You were talking with Kokomi and suddenly brought up a topic about your sister, you praised her, after which your girlfriend stood up, you followed her.

“If you love your sister so much, then live with her, and don’t follow me!”

She starts to get angry again, last time because of her you abandoned your friends, and now you have a choice between Kokomi and your sister?

"It's either me or her."

The girl said with disgust.