I think the girl is leaning in too hard too fast... dude wouldn't push too far just because of one incident now, and he doesn't enough about her to know how she sees it. Anyway, looking forward to this.
Usually 'its just a joke' makes me frustrated at an MC but im giving him a pass on this one. It was pretty easy to think it was a joke especially since they just met and he intended to tease the kids. Its probably more weird for her to take it so seriously this time.