After We Broke Up, My Ex-Girlfriend's Sister Took the Chance to Move In

Gu Bai didn't want to admit it, but he really had once been an emotionless little dog.

He'd kept putting up with it, only for the other person to push their luck again and again. Then, when they threatened to break up with him yet another time, for who knew how many times,

Gu Bai agreed.

At that moment, all he felt was relief and exhilaration.

Especially when he saw the other person's stunned, helpless expression. It gave him a thrill he couldn't explain.

But... can someone tell me?

After we broke up, they begged me to get back together with them, which was one thing. But why do they seem like a completely different person?