As much as I struggled not to think of him, I did not struggle to forget. I worried — late in the night, when the exhaustion of sleep deprivation broke down my defenses — that it was all slipping away. That my mind was a sieve, and I would someday not be able to remember the precise color of his eyes, the feel of his cool skin, or the texture of his voice. I could not think of them, but I must remember them. Because there was just one thing that I had to believe to be able to live — I had to know that he existed. That was all. Everything else I could endure. So long as he existed.
Bella Swan, New Moon, Chapter 4, p.116