Why does it alway happen when the wife is driving?

This is symptomatic of fuel pump relay ($25), radio suppression relay ($25) or Hall switch (or wiring from it) in distributor ($200+ for new distributor). You will find information on this in FAQ. If you have small a soldering iron, remove the plastic covers of these 2 relays and re-melt the solder on the traces and joints. I then still purchase the new relays and keep them in the glove box.

The Hall switch (part of the distributor) has it's wires coming out of bottom of the distributor cap through a rubber grommet. These wires may be frayed or near breaking. If that's the case, you'll find it best to buy a new distributor, since the switch is not mounted for replacement (unless you have a good shop who can drive the pins out and properly remount the new switch ($65)).

Intermittent problem are a real pain to diagnose for obvious reason. However, if you have a no start failure the FAQ has information on diagnosing the relay and hall. For example, fuel pump relay you can hear click and hear fuel pump buzz.

If you have to money, I'd take the approach that the car served you well for 12 years and put the money in these new part for preventative maintenace. That's what I do, if just to give peace of mind to my wife.