Big cock needed after pregnancy?

My wife is pregnant and it's her first. I'm wondering if after she's given birth is she going to crave a bigger cock to fill her pussy as she is never going to feel my slim 6 incher sliding into her stretched hole.

She has had some big cocks in her past before we met but as far as i know non since. She cums very easily and as such she's always said she doesn't really need a big cock to satisfy her, but i'm guessing she only says that to protect my feelings because when i fuck her with her big vibe she always cums like crazy, really loses control and creams herself. It's never like that when i fuck her, although she does cum.

I'm hoping that after she's had the baby she's really going to crave being filled properly again as i definitely wont be able to fill her and give her what she deserves. Has anybody had any experiences along this line that their wives have wanted a bigger cock after giving birth?