I suppose owning a pet, regardless of type, is in many regards similar to having a child (although, being childless, I acknowledge that this is pure speculation). Both pets and children find themselves in our care, in need our nurturement. Both have the peculiar nuances in their beings. And both present a paradoxical degree of joy and frustration.
I can only reasonably consider my pets as examples, but over the years I've had quite a few. Each has been unique beyond specific species or physical identifiers. They have personalities. They assert themselves in the world in individual ways. None of them has eve been, nor could be, a replacement for another pet, because they are their own entities through and through.
Most recently my wife and I acquired a new dog. of all the dogs I've owned, she has proven to be the most initially difficult with a willful destructive streak and a set stubbornness that makes her older dog sisters seem downright passive (and in reality, these older sisters are anything but passive). Despite the frustration new dog has brought to my life, a recent medical scare on her behalf, brought with it grave concern for her wellbeing, such that there was real concern about her survival. And I dreaded this, even though, logically, her passing would, in its own way, bring a form of relief.
This is something about love I suppose. I am not here, writing now, ready to wax too poetic about that. The point remains. Pets are paradoxes and yet I cannot imagine an enjoyable life without them.