Who did Natasha Romanoff kiss?

Steve 13. When Natasha (platonically?) kisses Steve at the end of Winter Soldier. Just a little innocent peck on the cheek before she tells him to be careful.

Did Natasha and Bucky date?

But in most of the comics that include both Black Widow and the Winter Soilder, they share a romantic bond. It is here that Natasha, who went by Natalia at the time, and Bucky formed a romance and showed each other that they were more than weapons for a country and realized that they were able to live free lives.