How is the concept of companionship represented in this book?

Niffenegger has based the entire story upon lifelong companionship after witnessing the commitment shared by her grandparents. Henry meeting Clare via time travel when Clare was only young and being able to be a part of her life as she grew and developed heightened the union Henry and Clare shared later in life. The pair knew each other better than most other humans could and shared a unique and complex partnership that at times appeared as though they were one. The two were individuals that shared many hopes, aspirations and traits in common but also had many differences. Yet, they always stood by the other's decisions and respected the others views. Henry of the present had a multitude of women who could not be compared to Clare. They lacked strength of character, determination and the will to succeed. Clare had waited for Henry for almost all of her life and understood him more completely than another ever could. Therefore, when they eventually found each other in the present, it seemed only natural that all other women would cease to exist for Henry. This is a story of the intensity love can have and the meaning of being committed to one person through extreme adversity and always conquering whatever battles life holds.