Hi cshapiro.
I guess the first two things would be to see it as either, a. let it be the worst problem to deal with, or b. it’s a kappara to “try” to let it be for the sake of your husband.
I know it’s not easy to shrug off things like this, and your instincts are probably right, and your husband said he does not mind doing more helping out than he is getting in return, so, the only thing I can say is that they probably dont spend that much “actual” time in your life, so when you cringe at the “assumption” you have to deal with them a long time, then dont think that. (I know that is not easy either.)
I think I once read in a book, “How to Stop Worrying and Start Living”, by Dale Carnegie Hall or Deli, I forget which, but he had something in there like imagine what is giving you upsetting thoughts going inside an elevator. Then picture the elevator doors closing and the object of your thoughts are no longer seen. Practice that over and over to mitigate the emotional connection to the object…something like that.
Hatzlacha!!