And here's the more important question: Do you WANT there to be hope for *this* M?!?
Look at what your H is doing to you! This is NOT a M. This is you carrying a sh!t-load of weight while H gets his family and his fun on the side.
You need a *healthy* M. Right now, you don't have that. You have to flip the script.
I'll try to expound more later, but if I were you, I wouldn't mention the concert anymore. I'd tell H that I'm not available to watch the children for him to leave so early because I already had plans that I had told him about, and I would strongly encourage my parents to text back that they aren't available to watch the children, either.
What better time than the present for H to start learning how to be a single parent? I mean, that IS what he said he wants, right?!?
M: 40 H: 44 Married 14 years S11 & D6; D20 & D19 from previous M 2BDs/PAs, 8 years apart Piecing: April 2014