"Don't even think about it, Captain," he admonishes gently, keeping up his soft attentions and his expression going soft as a result. "I know."

Knew that Steve needed his family. And knew that he needed Sam. And because he wasn't authorizing Cap-clones, he's basically resigning himself to this maddening tug and pull. It's better than not getting Steve at all, right?

"I get it." And he does. He wants Steve to have everything he needs, not just the things he can personally give him.