Pain
Pain is universal. Everyone suffers it at some point in their life, or unlife as the case may be. He watched her tease him, flirt with anything that walked by. Whoever said vampires don't love was wrong. He did love her. He wanted her back.
But she didn't want him. She ripped his heart and stomped on it, by being with him. It was only to spite him. he knew that but it still made his chest ache.
"Why are you doing this to me, baby? Why?"
He didn't want the pain anymore. But she wouldn't take him back.