I would go with ESH but I need more info. I think that you, the girls and your parents maybe ta, I'm on the fence about the husband and client.

Info: Why did you not listen to their explanation? Do they do things like this often? Were you just too angry or were you afraid to hear the answer?

I'm guessing that they thought he was cheating with this woman but why?

How long were they stalking him? Did they follow him to dinner or were they out and happen to see him at dinner and start taking pictures?

Who took the girls to the airport? Did anyone stay with them? What time did they land? Your parents were not expecting them back early so, was anyone able to meet them on time the other end?

Does your husband have a history of cheating? Did you know that he was having dinner with a client?

This is a lot of questions but I think this will help a lot.