Spouse:  I am tired of your stupidity.  You let people come over to the house and have the kids exposed to them in this pandemic.  You are risking my life.  I am going to talk to my lawyer and change custody.

You:  Thank you for bringing your concern to me.  I want you to know that I am careful who comes to the house.  I had a friend who was tested and we socially distanced wearing masks.  I will make sure to keep the house safe and practice social distancing.

Result:  There was no more discussion about this.