I guess I understand both sides of this, though. As a guy, it's engrained upon your very soul that penis size is everything. Girls seem to get the same thing about breast size.
I've never, to my knowledge, had a dissatisfied partner. I'm what I imagine is ACTUALLY about average (5.5" or so). Even with pleased partners in the past, I never really got over it until I started looking at it this way:
If the girl is happy, I'm happy... check!
Girls feel the same way about their breast size... I prefer smaller breasts. So, why assume girls all want monster dongs? check
Reasonably speaking, the bigger the better can't be totally true anyhow... at some point, it can't be comfortable anymore... check
So, using a little logic, I started to understand that average is not a bad thing. Besides... if my wife is happy with it, why the hell shouldn't I be?
)