Meet Lady. The only child, the queen bee, the regal princess, the ruler of her domain.
She leads a life of luxary not hampered by having to share her food, her toys, or her favorite spot to nap with anyone. There is no competition for attention. She is the one and only.
One day a foreigner arrived on her doorstep. Invaded her happy home, ate her food, slept in her bed and assumed the coveted spot in front of the door. Princess Lady was not happy.
As time went by the foreigner came and went in her life. At some point the little princess began to accept the stranger. You might even say they became friends.
They learned to share the bed, the toys, and the attention.
They even learned to share the coveted napping spot in front of the door.