“If the women on OkCupid calibrated the scale similarly, then the actual average man (2.3) would be considered significantly ‘below average’.”

Uh, sorry, no.

Based on your wife’s defined scale, where 3 is Average and 2 is Below Average, then the 2.3 score indicates that the average man is something above “Below Average” though not all the way to “Average”.

The word “significantly” here is inaccurate. And given your use of quotes around “below average” there is no doubt that it is inaccurate.

Remove the word “significantly” and you have a fully accurate statement, one that matches with the data and with your wife’s scale.