Ivy symbolizes the third party. It is not an object but a relationship.
A relationship on its own is an other existence. As we feed it and behave with it, it will develop.
It doesn't belong to the subject but develops independently.
In that the behavior, plays a bigger role than the quality.
The relationship will fade and wither or will expand and grow up like a plant.
Even if the relationship is of love or hate it will hold its subject as an ivy.
Keep the ivy elastic and don't have cirrhosis. The ivy can cover everything.