Unlike some others above, I would actually respectfully respond.
It may not make a difference.
You see, I have left a job before due to certain practices - namely, low pay. I worked for a company for 8 years that had low-ish pay, and like many companies - were stingy on the promotions and pay raises... so much easier to hire people at market rate rather than pay the people you have. It's a thing.
But the problem is, there were a few years where they had so much turnover (50%?) and NOBODY, in their exit interview, had the balls to say it was about money.
I said "it's the money". Because - they need to face that. Whether the organization does anything, it's up to them.
If you say nothing, nothing will happen.
If you say something, maybe nothing will happen.
If your wife clearly states:
"I have been turning down these requests for a few years because it makes no financial sense to do X amount of work for Y dollars. However, this year, Boss #1 offered 2x the hours for 2.5x the pay - suddenly, it made more financial sense to take on the additional work.
You have now cut the offer back to the original - the one that I turned down over and over. It is STILL not worth the money. It is not my fault that you are now in a bind. I was interested in offer A, not offer B."
A clear response tells Boss #2 that:
1. You are not being an asshat - you had a specific offer
2. You have a clear definition of what is "worth the work"