Dad. To him, it was a loaded word.

It was what he had lost. The cheeky-grinned son that Sara swore was the spitting image of him when he was in trouble. Tucking him in, or gazing through his telescope together.

It was what he had. That unspoken thing – I'll call you Dad, but I won't touch your daughter. It was an arrangement that both men could live with, though Jack suspected and Jacob knew that Selmac laughed at them both.

It was what he would never have. She'd gift the title of Dad on someone else, and he'd be lost.