I didn’t know
What you say when you didn’t know something, and you’re too lazy to admit it, especially if the other person has been nagging you about it since the beginning of time.
'I didn’t know you had a kid from the 90s! I thought you had a kid from last week!'
'I didn’t know you were married to a chicken! I thought you were married to a chicken from a different state!'
'I didn’t know you had a mortgage! I thought you had a mortgage from the 80s!'