Natasha appreciated his acquiescence. More than he would ever know or understand, probably, but when she could, she liked to look a thing in the eye and call it by its correct name. So much of her life had been about illusion and subterfuge that when she could, when she needed it, she tended to railroad until she was given the truth. Even if it was an ugly truth, even if it was sharp and cold and unkind, it was what she preferred. Directness won more credit from her than kind sentiments ever did. Kind sentiments weren't the sort of currency you could spend. Bucky didn't want her to die, but that want did neither of them any good, and it meant that she'd rather hear the truth of it out loud - if given the choice, I would choose him, not you.
She did not like ambiguity. It was easier, when you knew exactly where you stood with people. And you always stood somewhere, in the end.
Anyway, he was right. What was done was done, now, and if there were all sorts of things she could have shouted back in return - that Steve was still perfectly happy to sacrifice all of them, that he hadn't even pretended to be all right with the plan the rest of them were trying to get rolling at Tony's, that as long as a revolution came he didn't give a shit if the cost was everyone else's life when no one else had agreed to turn their life over - well, they'd go around in circles. And Bucky had already given her the only thing she'd wanted, which was honesty.
There was nothing else to ask from him.
So she looked at him for a moment as they walked on, a long, hard look, then turned her eyes back to the path in front of them. Clint's building was only a few blocks from here. "I hope he knows how lucky he is," she settled for saying, instead of he didn't deserve you. "That you loved him. Knowing that's more than any of the rest of us ever got to have."