Oh man, Im sorry, thats pretty lousy of her. Maybe he needs to ask her why she would lie to him!
I guess that I would try to tell him not to rush to conclusions, you dont know for sure that shes lied, maybe she just wanted that shirt. You cant know for sure that she even went. And then I would document that she abandoned the boys yet again, and write down exactly what S12 said.
My question is, whats your 38 y/o wife doing going to see a kiddie band? By herself, or with a friend who is taking her kids, or what? I ended up at one of those concerts once, there was no beer garden- big mistake!
I guess I gave the wrong finger to the wrong man...