i know the feeling..our previous house bun could never be trusted with the sofa!
Oscar was as good as gold until my cat died and then he took to toileting on the settee..
he got better once hed bonded with Bif..before that i put his litter pan wherever he used the sofa..he seemed to be ok..but then he did it again....
last time i blamed bif for doing it..but to my shame realised it was the little fella..my daughter lays on the sofa a lot where shes so weak and she has a sheet on the sofa and various pillos and cushions to help prop her up...
oscar had peed on the sheet and puled the cushion over it!!
he still does try..he gets caught short and instead of risking running back to pan in crate..he heads for the sofa..watch them and you see them sniff the sofa nd then spin round to face the other way and appear to be washing their bits..you then find poos and know the wee is next..so i shoo him off sofa dn he runs for the crate..but then pretends he doesnt need to go.till he thinks im not watching him..then he floods the litter pan!!
I clean the sofa with white vinegar usually and then add a textile spray and then give it a blast with my steam buddy..
or i spray on cascade antibacterial small animal disinfectant..it works like a charm and doesnt stain or bleach fabrics!! and then damp it off and dry..
if you ever find a way to prevent this from re occurrring let me know!!!