Buffymad, I don't agree!! you are leaving that dog alone all that time, A jack Russell is not a dog to leave alone like that, I see it as selfish!
How do you know your dog is happy? just because he doesn't wreck the place?
"If you're comfortable with leaving a dog alone, he or she would get used to that routine"
what a selfish statement to make!!!
When getting a dog you need to consider what is right for the dog, not just yourselves, the fact that the dog tolerates being left alone for hours at a time does not mean the dog is happy!!!
and no I don't think the dog should be put down just because you cant find the time for it, I think you should attempt to re-home the dog with someone who can give it the time and energy required to look after any dog!!