Jo had stopped when Cas spoke up, turning to Dean as well, a look of concern in her eyes. Her free hand rose and lay lightly against his cheek. "Hey. What is it? Talk to us." Her voice was quiet as she'd been keeping it lately, when around the two of them, at least, because it was easier to control the moodiness brought on by going cold turkey. There were times when she almost gave in to the urge, but then she'd look at her phone and there would be a text from Dean, or she would look up and see Cas sitting in the corner, and she would stop.
She was determined to be there for the two of them, as well, and quit being such a crappy girlfriend.