What is the difference between women aged 8, 18, 28, 38, 48 and 58?

 8 years - you put her to bed and tell her stories.  

18 years old - you tell her stories to put her to bed.  

28 years old - you don't even need to talk to put her to bed.  

38 years old - she tells you stories to put you to bed. 

 48 years - you make up fairy tales so you don't have to lie in bed with her.  

58 years old - you don't get out of bed so you don't listen to her talk