5 years old son,
After watching a story of an Emperor on TV:

"Mum, I also want 7 wives, one will cook for me, one will read for me, one will go for walk with me, one will sing for me,one can bath me,...."

Mum smiled and said:
"Then night time I don't have to accompany you to sleep!"
After some thought, son said:
"Not possible, I still want to sleep with you mummy!"

"Then who will sleep with your 7 wives?"
"Let them sleep with daddy!"

Dads eyes fill up with tears of happiness:
"My sweet son!"