Chris, I too went through that, too much times... and every time, one just cannot believe it hurts so much, and to bear it once more seems impossible... but... Today, while I was at the vet's with Rompi, there was a lady with a black kitty, female, two years old, with asthma... she was black with a small white whiff under her neck... she was just so MAGIC, with that look in her eyes, so tender... the look of "the good cat". I was about to steal her right there! :) In that moment I understood that, notwithstanding anything, it's impossible to live without cats, and that the horrible, exhausting experience of "letting them go" is the toll for what we have received from them during their life. We could discuss if that toll is fair or too high, but that's it.
Paolo P.S. I'm going to call the vet's to ask when the black kitty with asthma is scheduled next time... ;)