If you don't want your husband to know you went to...let's say....for example Fleet Farm to quick pick up a Christmas gift for him (even though you said you were going to drop off an overdue library book that you didn't want to continue paying late fees for as it sat on your nightstand, which is the truth but not the main reason to get out of the house)
...don't take your 3 year old along for the ride.
Because, once he asks you, "What took you so long?" and you reply with "I just had to make a quick stop somewhere else" but you refuse to tell him where...
...that's when your darling 3 year old might pipe in with the most excited little voice, "Daddy, I love going to Fleet Farm."