@Lanthom,
That's a tough one to my way of thinking. Another dog, and a large one at that, is totally unsuitable to your household, and I would not like being told it is going to happen in spite of your objections. I guess if you can foresee this kind of problem off into the indefinite future, and you're really at your wits end, you might as well get it over with. You know it's going to sound really silly in court if you don't present it just right, but only you can make the decision.
Sorry for the non answer. I don't think a good answer is going to come along.