Why the fuck did ex's even cared to call again?

My ex called me again after we brokeup 6 months ago. She found someone else just after a week we brokeup and then called me saying how perfect that guy was and how much available he was. People always says that rebound never lasts but even though she got into relationship with a toxic, fuckboy, immature guy who cheated on her, still she gave her second chance. 2 days ago she called me but I didn't picked up cause I was still dealing with the trauma.