Bucky and you were in a long term relationship, up until thanos happened, the day before the fight he spends the whole time with you. And when the blip happens, you watch him turn to dust right in front of your eyes. The words "I love you, forever. Never forget that." Being the last thing he told you, the smile, tears shed. Now years pass into the future, you have a daughter with another guy and he calls about her.