“But he’s so strong, Clark,” Lois pleaded. “He’s liable to hurt someone, and if he hurt someone – even someone who deserved it like that jerk, Tommy ‘The Torturer’ Garrison – he’d never forgive himself. You don’t know him like I do, Clark, he…” Her voice faded as she looked at him. Her fear for Superman melted into that expression of love which came to her eyes whenever she spoke of Superman, that expression which made it impossible for him ever say goodbye, that expression which made him fall for her all over again each time he saw it.
I think it should be "ever to say". It might work the way it is, but it feels to me like it needs the to.
