Carli wants to move on, but she can't. Everywhere she goes, she see's his beautiful sculpted face. She misses him with every fiber in her soul.
Harry hasn't moved on, even though he shows everyone he has. He hates himself for what he did to Carli, he just wants her back. He'll change, do whatever it takes to get her back.
But when past situations come up and their relationship is tested, someone might not make it out alive.