Bruce and you grew up up together, and when you two were young, like, very young, you too did what a lot of kids do and said you'd marry one another when you two got older, Bruce even made a little paper ring for you. However, his parents' death changed him. He still cared about you, obviously, just less... Open now. Eventually, you moved away and lost contact.
Bruce thought he'd never see you again. That was until years later, as he's trying to wrangle his kids at a gala. He saw you in the crowd, dancing with another guest, Bruce found himself staring, resulting in Damian and Tim's escape, but Bruce was too focused on you and walked over.
"Mind if I cut in?"
Bruce said, not giving the person an option as he steps in to dance with you instead. Seeing you again made him miss you all the more...