Smithduke,I had a kitty with cancer(peppi)hubby adored him,did not want him put to sleep,one morning however,Peppi was crying in pain,I called my vet and said I am coming with Peppi.
When my husband woke up(he worked nights)he asked where Peppi was,I pointed him to the carrier outside on the deck,where Peppi was.
Yes,he got very upset,had a quiet moment with Peppi,then buried him in a special place in our backyard.
Maybe your kitty will have some more time with pain-meds,Peppi did not,he was also diabetic.
I understand the love your husband has for your cat,we did too for all our cats and still do,we wish we never had to make the life/death decision,but unfortunately it's all up to us.
"The cruelest animal is the Human animal"
3 kitties,Rocky(r.i.p my boy),Chico,Vinnie