The thing to remember is that Casino Royale is very much Bond’s origin story, it transforms him to the man he’s going to be. Vesper’s betrayal really codifies his misogny.
What I always liked about the literary Bond is that he’s not an unstoppable killing machine, but rather a man who refuses to quit. No matter how hurt and wounded he gets he’ll just keep coming until the mission is complete, though that will weight on his both physically and mentally afterwards. The only way to stop him is to kill him. Dr. No, while not a particularly good book, really drives home this idea since it’s main point is to re-establish Bond’s faith in himself after he nearly dies on a mission.