Perhaps she can't get pregnant, or he's shooting blanks. That's really not something (especially for girls) you know until you try. There's also the POV that she was too thin to get pregnant, although if Courtney Cox can do it I would think anyone can.
When you're in that first glow of love things are different - this and that sounds good, then years go by and maybe it doesn't anymore. Especially in their business.
AKA2D, when I read this and then your "Every Day is a Day of Thanksgiving" sig line directly following it just seemed way too appropriate and I had to laugh.