Dude ...
Length is one thing.
Width is another.
And then there's the helmet, size between tip and base, etc...
Why are you so focused on one dimension, let alone size at all?
Dude, I'm sure I don't get my wife off like I used to when she was tighter.
Over a dozen years of hammering her pussy tends to do that.
So should I be worried nowdays?
I mean, I could find other men that could take care of her better.
Dude, don't worry about it because it's really nothing you can do about it.
Besides, there's a lot more to ensuring her pleasure than your stick.
Although if she hasn't had a lot of dick in her, it's not going to matter until she has (whether it's only yours or not).
Don't think about this again, seriously.