Okay, usually I headcanon Barb as a lesbian but maybe in this AU, she isn't, or maybe Steve is the exception or she's pansexual. . .
Writing prompt: After Nancy sleeps with Steve, it's Nancy who goes missing. Barb wants to hate Steve so badly and wants to blame him, but when he steps into help while risking his life to save Nancy, she can't help but feel something else for him. And as much as she hated him calling her Barbie, she kind of liked it, especially the way he smiled when she called him Stevie. When they bring Nancy home, how does Barb explain to her that she developed feelings for her boyfriend? It's Nancy who comes up with an easy solution.
Plus. . . Can you imagine how Barb would react to the photos? I think she'd praise Steve for holding back.