Can a lawsuit for slander be declaired if they plaintiff slandered back?

I recently posted to a public forum thoughts and opinions about events from a divorce without actually naming the family and this person is now claiming they have obtained my personal info to link me to the my poster name and they claim to have an automatic win for a lawsuit, but yet this person posted back to my comments under 2 different user names and slandered me back admitting they know who the family is, attacked my character and then telling my user name under another poster name to retain a lawyer, wouldn't these actions cancel out his lawsuit b/c thye are just as guilty, plus no false statements were made, and defamation to character doesn't apply b/c no monetary loss can result from this, if the claim is unneccessary "mental" grief don't I have the same complaint? They have told their children to har mine and are the ones telling my kids were gonna be sued for everything b/c of what your mom did, aren;t they just setting themselves up for a loss at a countersuit?