One can only hope that she was playing him right back, planning to amuse her girlfriends later with the story of that horn-dog married guy at the store today, what a tool.
It's not his childish insistence on getting you back that bothers me most, though. He was obnoxious to the cashier and toolish to you, but not understanding why you'd mind these things makes him an idiot, and that is pretty close to unforgivable.
You will forgive him, of course, after explaining one more time exactly what he did wrong. You pretty much have to, since you don't, I assume, want to have to get a new husband. It's hard enough to get a new grocery store, and I don't see either of you going back to the old one, do you?