His skin positively burned where she touched it yet the shock at having her physically grab him and issue such a command managed to keep him from surging away from her yet again. Instead he gave a sharp shake of his head, lips pressed together tightly, and he likely would have continued to refuse to speak to her about any of it... if she hadn't sounded so very frightened when she spoke next.
Spock loved her. There was no doubt in his mind about this and nothing would ever change that fact. It wasn't logical, it wasn't appropriate, but he didn't care. He loved her and he always would. Which is why he couldn't bring himself to lie to her by claiming there was nothing she could do to help him. Because there was something she could do. He was just loathe to ask it of her.
"I will not allow myself to hurt you."
The words were spoken at little more than a whisper. He met her gaze and forced himself to hold it. "If I take a mate, the pon farr will pass as it is meant to," he explained gently, in a clipped tone. "However, the only mate I would consider would be you, Nyota, and to do such a thing would... hurt you. That is something I cannot allow."