Awwwww! big hugs to you.
I torture myself over the very same thing and it's horrible, but you know when it's time, Jaypot said this to me when Bob was so very poorly and I really didn't understand it and then one day I just knew, but I always think you feel giulty about it because you are the one making the decision.
I really agree with Donnamt, it's all about quality of life.