He eases up on her hand—she might need it later—and turns his thoughts away from Rey. They were having a nice time before she came up, weren't they?

"I should go see my father." The way that he doesn't let go of her hand or make any move to go suggests that this isn't a thing he wants to do. Staying here with Kitty, unable to do much more than hold hands, isn't that appealing, either. He might forget himself and hug her.