I don’t remember the exact quote, but Jefferson said something to Regina about her dragging him to SB. I don’t think he was affected by the curse, but that Regina brought him there specifically because she knew she might need his abilities. They also hinted in “Hat Trick” that there is a strong (possibly familial) tie between them that goes way back, so I think there is a lot more to the Regina/Jefferson story than we know at this point. Either way, I adore him.