My cat Sparky was diagnosed with an aggressive cancer 3 1/2 years ago. She went through surgery, radiation and chemo, and the cancer went into remission for over three years. The past three years have been the happiest years of her life.

A couple of months ago, the cancer came back and it was so aggressive I could literally see it grow every day. I devoted hours each day to her care, cleaning her tumor (it's on her face), taking her to the vet, trying to get her to eat, administering medicine, and just hanging out with her. Since Olive was born, I don't have nearly as much time for her, but she was still pretty happy.

The past two days Sparky has been sitting in her litterbox and hasn't come out. This is a decision I've wrestled with for some time, but I think it may finally be time to put her to sleep. I don't want to wait for her to slowly deteriorate or be in significant pain. We have a vet that will come to our house to put her to sleep, but thinking about the finality of it all is making me so sad. Is this the right time? I've asked myself this question almost daily the past couple of months. She has been unbelievably happy through all this, eating well, playing well, despite having an ulcerated, open tumor on her face.

Sparky is 10 1/2 and has had a great life. I just wish she had a little more time, but I feel so lucky for the extra years we've had together after her initial grim diagnosis 3 1/2 year ago. She really is the best, sweetest cat ever.

Have you ever put a pet to sleep? How did you know it was time?