There was no backslide there. If that dialogue is an accurate description of what happened I rather feel it is an excellent example of how to have a discussion, validate while disagreeing and show your spouse this is not what you want. Others shold read it to learn how to do it.
And backsliding, that's not always bad either...or what people think is backsliding. Sometimes oyu've got to push, you've got to vent at your spouse...because venting here isn't getting the message to them.
She reacted and you responded. Beautiful. Every action has an opposite and equal reaction. MLCers react; it is something done an autopilot. You responded with forethought. And her reactions were waht we can expect right now...of course she accused of not validating and such. Your job is to remain consistent through that. Reacting is biting the bait and allowing an argument to escalate. Responding is letting her stand there and argue while you don't. She will think you had an argument, but thse won't relaize she had one with her Self only. Hopefully she will catch on and stop trying to push more to find your weak spot. She may then find someone else who will react or stop pushing and move on to other tactics.