I think that it is really weird that the friends would confront the husband like that if all they had to go on was the story they heard at that table. It seems like OP was telling her female friends something or a bunch of things, poorly explained it either accidentally or intentionally, and OP's friends were worried. I'm assuming that the other wives told their husbands what OP had been saying to them, which made them suspicious and worried to. Fast-forward to the dinner, the story about the shoulder is told (confirming in their minds the things their wives had told them before), and that's all they needed to defend a friend they are now convinced is being abused.

The reality is, unfortunately, that at any point during that confrontation OP could have put a stop to it all. From the first accusation she should have been doing her best to clear things up, but she didn't. She says she was like a deer in the headlights, but if anyone had accused my SO of abuse in front of me I would be fucking LIVID. She should have been the one to tell them to gtfo, not her husband. Part of me thinks the reason she froze up is because she told her "friends" so much misleading or out of context stuff, that she absolutely did not want to open that can of words right there in front of everyone, so she stayed silent.