Aw, I am so sorry. As I see it, you did not abuse the animal. You did one thing wrong only - you yelled so loud that he went to the bathroom on the floor. The rest of what you describe - water and all - are common and innocent pranks that some cats and cat owners enjoy. Then, the cat was there for you. I can picture that - when I am in danger from not sleeping and anxiety and all, my two cats are right by me, as if on a vigil.

Apparently, the woman who brought the cat into your apartment has since defected. You ended up living with an animal you did not mean to own. The woman was exceedingly strange in her own way, because not to tell your partner, however LD the r/s is, that you own a cat is not something that an average person would do.

So you went out of your way, gave the cat a very good life, had a very good parting and the last good bye with the cat, rescued other cats... why do you still feel guilty? The killer was silent - there were no lapses in care and nothing could have prevented the death. 8 years is not so young, either.

Objectively, you should be grieving, but content. Content that you gave this animal a good life even though you got stuck with him against your will.