动态记忆的删除是如何真正起作用的

我主要有两种类型的对象：Person和Pet。一个人可以养很多宠物。我正在动态地创建这两种类型的对象。

#include <iostream>
#include <string>
#include <vector>
struct Pet
{
Pet() { }
Pet(std::string name, std::string type)
{
Name = name;
Type = type;
std::cout << Name << " is created" << std::endl;
}
~Pet()
{
std::cout << Name << " is destroyed" << std::endl;
}
std::string GetName() { return Name; }
std::string GetType() { return Type; }
std::string Name;
std::string Type;
};
struct Person
{
Person(std::string name)
{
Name = name;
std::cout << Name << " is created" << std::endl;
}
~Person()
{
std::cout << Name << " is destroyed" << std::endl;
}
void AddPet(Pet& pet)
{
Pets.push_back(pet);
}
std::string GetPersonsPets()
{
if (Pets.size() == 0)
{
return Name + " has no pets";
}
if (Pets.size() == 1)
{
return Name + " has " + Pets[0].GetName() + ",a " + Pets[0].GetType();
}
}
std::string Name;
std::vector<Pet> Pets;
};
int main()
{
Person* peter = new Person("Peter");
Person* alice = new Person("Alice");
Pet* fluffy = new Pet("Flyffy", "dog");
peter->AddPet(*fluffy);
std::vector<Person*> People;
People.push_back(peter);
People.push_back(alice);
int i = 0;
for (std::vector<Person*>::iterator it = People.begin(); it != People.end();
it++)
{
std::cout << People[i]->GetPersonsPets() << std::endl;
i++;
}
//delete fluffy;
delete alice;
delete peter;
}

一切似乎都正常工作，但当涉及到删除宠物对象时，会发生一些有趣的事情。当我取消对delete fluffy的注释时，floffy会在peter之后自动删除。

我想，既然蓬松是动态创建的，除非我自己做，否则它永远不会被破坏？

但当我不取消对delete fluffy的注释时，会发生另一件有趣的事情。然后它的析构函数将被调用两次。

怎么可能两次毁掉一件东西？