This is a really provocative thread, and one I wanted to reply to because I'm actually very scared right now about this becoming a real possibility for my Pet. She is severely overweight and suffering from that alongside her disability, so she also has sleep apnea (which has a surprising rate of sudden deaths) and is considering undergoing gastric bypass surgery (which, while not technically a "risky" surgery, still carries with it the possibility of mortality.)
When my first relationship ended, I thought my life was over. I could barely hold it together and I only made it through because of my Pet. Even so, I have remained friends with the boy I had been dating to this day, and that helped ease the pain. If my Pet, whom I love much more deeply than I ever cared for that boy, were to pass away, I think my heart would just break. It is very likely I would commit suicide, frankly, or have to be institutionalized due to my mental health issues. She's the glue that holds me together and I can't imagine a world without her.
That said, I'm so glad I have her here with me. I should be thankful more often.