I always had trouble convincing my ex that driving through mountain passes in 4th gear overdrive in rain, snow, or ice was not the best of ideas. My suggestion to OP is if possible. Drive the vehicle yourself. Otherwise you are in a no win situation.
My cruise control system is limited by the ECU to speeds above 25mph. It’s useless in stop & go traffic. More’s the better. I wouldn’t want to use it there anyway.
Yes, I do have an idea. Disable the cruise control, and pretend it’s broken. And make sure it’s broken in a way that can’t be fixed. 
Or get a car like mine…
I wonder just what part of “cruise” does your wife not understand?
Reminds me of a joke. A cop pulls over a guy for speeding. As the cop looks like he is about to write out the ticket, the driver complains vociferously that he never speeds and wasn’t this time. The cop leans in and seeing his wife sitting next to him, asks, " Lady, would you remind your husband how fast he was going?" To which the wife replied, " I know better then to argue with my husband when he’s been drinking."
I guess sometimes you just say nothing.
It can really annoy a person, how some peoples driving habits are.
@Pvtpublic; had a good idea to puke in her lap, but my first thought was @Jesmed1 suggested.
Just diable the system by pulling the fuse. Or have your mechanic in on this too so she doesn’t have him fix it.
My Brother in law was one of those who thought his car… 74 Camaro… would sound better if he always accelerated a little then let it coast . Accelerate, coast …accelerater, coast.
He would fluxuate about 5-7 MPH and it drove me nuts.
MY wife also has some bad habits besides burning water or air on the stove.
Getting on the interstate highway one day as I followed, she entered the ramp and sped up to the flow of the traffic. As we merged, a convoy of National Guard trucks had just passed. Because of the governors on the trucks…they were traveling about 58-60MPH. She passed the last two trucks in the convoy and pulled back into their lane. Then proceded to follow the rest of the group for the next 15 miles until we had to exit. THere were plenty of spots where she could have gotten out and passed the rest, but no…we had to follow the whole group while the rest of the traffic was zipping by at 68-70MPH.
Yosemite
What kind of car is it? If it has an automatic with a manual mode, lock it in the highest gear that the computer allows. This prevents downshifts and minimize the sudden surge of power.
Disabling the cruise crossed my mind also but that brings up the question as to whether or not the better half is going to demand a brand new car with a working cruise control…
Yep, Dr. Phil or race her to the car and you drive. Just remember “A woman convinced against her will is of the same opinion still”. Is this the way her dad drove I wonder?
Our son had a lead foot when he first got his licence.
While he was away one day, I opened the hood and located a spot in the throttle body where I wouldn’t interfere with anything. I drilled a hole…tapped threads nito it…and installed a screw that would limit the opening of the throttle plate. This way he was limited to about 3/4 throttle at all times.
I know I took the chance of limiting his power when he might really need it, but I had to take the chance so I wouldn’t be attending his funeral.
Where did I learn that trick…my dad did it to a Mustang that my mom wanted in the mid 70s.
He said that she scared him so bad riding with her…he had to do something.
yosemite
I’ll second the lap delivery or the fuse pulling. The fuse might control something else, so look at the diagram for your car before you do this.
Do you like when your wife tells you what to do? She obviously doesn’t appreciate your criticism, so it’s either time to let it go or get marriage counseling.