Over the holidays, I was at a party with some friends. One friend (f) was there, and we talked for a while. I later saw her go to the door and greet her boyfriend. I'd met him before at various parties, they'd been dating around 6 months. He'd brought his kids with him, who we'd never met. His girlfriend met him at the door (not her house) I jokingly made a comment about their lame side hug. Apparently he hadn't told his kids he was dating anyone. At dinner the other night, they brought it up and told me I'd single handedly spilled the beans to his kids, and the tone of the conversation wasn't jovial. I do feel bad, and I did apologize, but the more I think about it, the more I'm annoyed (on the verge of being pissed) that I was put in that situation.

If it was that big a deal, why couldn't she subtly mention it before he arrived? There was probably an hour at least and it wasn't that large a group. And why would you bring your kids to a party hosted by your girlfriend's friends (he knew everyone through her) and expect no one to mention it? This wasn't a new relationship, I think it's reasonable to presume after 6 months he's told his family. 

So AITA? 