How do you deal with an 'on the way out' pet?

I have had to put 1 down and another died naturally in recent years, both dogs. each time I tell the wife lets wait a year but she brings another home within 6-8 months. so its her decision to bring a new one home. she picks good ones. .it feels terrible each time but the new pet is just as much fun and satisfaction. they are each different and each one doesnt replace the other, its just a different or new furry friend. So dont think of it as a replacement pet think of it as a different pet if you get a new one.