Your assumption is WRONG. You will never be asked by Social Security if you want your spouse to have a death benefit. Your spouse automatically gets a death benefit of half your benefits (which might be subject to the “offset” for her teacher’s pension) –if you are married at the time of your death, or if you are divorced, but she was married to you for at least 10 years and is not remarried. It is NOT a choice that you make, and it does not reduce your own benefit. You get what you earned, no matter what. For complete details please read the article at this link.
One more thing. If you are a union employee, you may be asked if you want your PENSION benefits to be reduced by covering your life and that of your spouse. That will not be impacted by the Social Security offset. And if you can live on less, it would be a good idea to elect PENSION survivor benefits.