What could he say to breaking a promise? Or to loving her? It was because he loved her that he had to leave her. He had to; he just couldn't see any other way.
He was barely able to meet her eyes, and when he did, he wished he hadn't. She was so beautiful and amazing, and she was his. He didn't deserve her, not in the least.
"Don't say that, Dora," he begged her. "I know it's hard for you to understand, and I do love you." He meant it, with every bit of his heart, and that was why he knew he had to leave. He exhaled slowly, a long, shuddering breath, and then got to his feet.
"I just -- I won't ruin my child's life, or yours. You'll be better off without me. Stay with your parents. They know it's true."
And if his child was a werewolf, he was certain Dora would come to the same conclusion. She wouldn't understand once her baby went through the pain. She didn't know what it was like, to scratch and tear at yourself during the loneliest nights of your life.
He physically ached, knowing that he had to leave his wife, and his child. It had been a long time since he'd experienced love - and none that was quite the same as Dora's - but he couldn't see it ending any other way.
"It will be better if I go," he told her, and a bit more harshly than he would have liked, but he didn't want to break his resolve. He was doing this because he loved her. It was best.