A couple will figure it out after a while. I don't think there is a scientific absolute. A woman may prefer guys my size for comfort, then meet a guy hung like a horse but more compatible and she will probably teach/coach him how not to be an "uncomfortable" fuck.
I know must guys are fascinated by the world penis, but the vagina is an equally impressive creature as it can expand and contract to accommodate different size objects such as the penis, the dildo and then the ultimate destroyer a "baby".
Lots of gifted guys here but haven't scene one with more girth than a small cranium