He was... happy for them. Proud they'd won free, proud they'd found a place. He'd like to see that, someday. But for him... he had a place, now. And it might be lonely, and all-consuming, but... he was needed. And he was the only one who could do the job. He'd proven that, when he'd beaten Sato. "I'm glad," was all he said.
Perhaps someday they'd wipe out the cybermen, so no one else would have to overcome this curse.