Nanase is a POS for shoving her friend.
Ong, just break up. If you know your GF is cheating and you can’t even be overprotective, and at the very least, check up on or, or idk, NOT leave her alone with the same chick she cheated on you with?
She could’ve totally made up an excuse to stay.
“I’m the one who bumped into Yuni so I want to stay by her side and make sure she’s okay”
Assert your dominance and be aggressive to the folks who deserve it, not the chick who’s on your side!