She and I have been together for 17 years, and I can't imagine the house without her, but she's been increasingly sick (as most of you know) for more than two years now with renal and intestinal ailments, and in the last month or two she has developed some (possibly senility-related) behavioral problems. It finally just seemed like it was time.
I'm usually not a fan of euphemisms -- they often simultaneously amuse and annoy me -- but in this case, I find myself shying away from the words "die," "dead," and "kill." That's what will be happening, of course, but for right now I'm just going to spend some time with my cat with an awareness that this time is fleeting, and avoid those words even in my thoughts as much as possible.