Ruby asked, what was the difference between her question and her coworker's question.

I would say that one difference is that the coworker asked for further information about the 3 children that were already a subject of conversation, and probably it had been mentioned that it was a blended family?

But Rubys question implies stuff like, "did some of your kids stay with their mother?" Which is none of her business. Or "is your ex-wife a floozy?" - which im sure she didnt intend, but might be how a guy would think.