Belly talk

I often tell Ethan stories of "when you were in my belly" and he listens and giggles away. So last night, we are having dinner and he looks up at me and says "mommy, when you were in MY belly we went to Quebec City". I tried to tell Ethan, that I was never in HIS belly and he was very hurt. He said "yes you were Mommy, when I was a baby and you were a baby" very indignantly. I tried to tell him that he was in my belly, but I was in MY mommy's belly. Apparently I am very wrong.