Why does my boyfriend do this?

My boyfriend is constantly confusing his ex's likes and dislikes with mine... For example I've mentioned that I only like BBQ sauce with my chicken nuggets and he always brings back ranch saying I know that you don't like BBQ sauce which of course was his ex that refused to have BBQ sauce. And then there's the lesabre that she drives and the Arizona license and the gravy... I don't really want to go into detail about all of it but almost everything he talks about has nothing to do with and everything to do with his ex (J. L. A. P)
Why does my boyfriend do this?
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