I get depressed and want to kill myself after reading stories like this, I can't imagine the state I would be in if this actually happened to me. Knowing myself though, that would be the tipping point, I would completely abandon humanity and commit acts that would go down in history as completely atrocious.
First off, I'm inviting all the kids back to the house with their mom, I'm tying everyone up with cable ties, and locking all the doors, will barricade us inside. I'm taking my one biological child and tying them up in a separate room, blindfolded and ears plugged.
I'm raping the cheating whore first, then all non-biological daughters are getting raped and killed in front of the mother, all non-biological sons will then be killed in front of the mother.
Then i'll untie my biological daughter, and then blow my brains out, i'll leave that mess for the living to deal with.