Ouch. I had an ex who did that. Drove me absolutely round the bend. I finally called her on it and said "I'm sorry, but I can only deal with things as they were, not as you would like to remember them."

And that, as they say, was the end of that.

(What drove me even more insane is that that behaviour is one she'd routinely call other people on and castigate them for. A friend of mine observed, "Well, of course. If she let other people get away with it, you'd have two people lying, and you'd NEVER be able to figure out what was really going on.")

My deepest sympathies to you both.