Tree or a bird??
A tree stands still and firm in a place with its roots penetrating deep and strong into the ground. Tree evolves from a seed, grows to give food and shelter to all. It stands tall, letting all the birds that flew in from afar to make the branches it's home. The bird built a nest, lay eggs, gave birth to its offsprings but later flew away to another tree. But wait, what did the tree do? Happily nourished and stood strong to give the bird a happy peaceful halt.
The tree doesn't blame the bird for using it and later flying away, nor the bird does something in return as a favour for giving it shelter and complain about how the tree isn't enjoying its life by travelling around the world. It's not the fault of the bird or the tree. It's Nature. Just like us where some choose perseverance and entrenchment over vigour and ephemeral lifestyle. Nature accepts the nature of others, then why can't we?
Alive to accept and adapt!