Mostly because I can’t be arsed with dealing with it?
DH at the grand age of 31 still hasn’t had chickenpox apparently. He was around kids with chickenpox as a child and never got it so is possibly immune. DS will be 2 in a couple of months and is at nursery so does have the potential to pick up CP and bring it home. I’m pregnant with DC2 and can’t think of much worse than dealing with a toddler with CP, and a newborn, let alone if it turns out DH isn’t immune.
Would the GP check DH’s immunity do you think? If he’s not immune, I could just get them both vaccinated. I’m generally speaking a bit suspicious of anything that isn’t part of the routine schedule (not an anti vaxxer at all obviously, just trust the experts to make the right decisions about what is offered) but it all seems perfectly safe.