I'm right there with you! In both Sims 2 and 3 (and even the original), as soon as Pets came out, I've not played a family without pets!
Lol, it's so bad with me that Panther probably will have to change his LTW as I can't stand the thought of giving away one of the Dogs to make room for the fifth child for his Lifetime Want. There is an alternative, which is to wait for Pink or Banksy to pass on, but then that child would not have a shot at being heir as the heir poll will be a while before that I suspect.