I would be happy her perspective is that your M3 is slow.
That means she would not be interested in driving it much.
My wife doesn't like to drive my M3 or 335 because I am so anal about the cars however her 13 Outback and Ford 500 she has no issues driving.
Mine drives off our driveway with no slowing down and wham goes the suspension no matter how many times I tell her to slow it down.
We all have our life partner issues...