I have no kids, so no ingrained "overreaction" here ...
I think this is such a hot-button issue because the Mrs. is saying, in effect, "I am so furious with you that I no longer wish to participate in doing something good for your child." That, in my mind, translates more-or-less directly to "I do not actually care about your child as an individual at all, but view them as nothing more than an effective club for me to beat you with when the occasion merits."
Maybe that's not how she means it. But that's how I hear it. I've heard very similar things before from unstable (translation: diagnosed-mentally-ill) individuals. It's some seriously ugly mojo.
Ugly enough that, at some point, who cares where it's "coming from".
"Show me a completely smooth operation and I'll show you someone who's covering mistakes. Real boats rock." -- Frank Herbert