I agree with Giselle, see a behaviorist before you give away either dog! It sounds like youre confusing the pack hierarchy, AND you are allowing the JRT to be alpha over you. You definitely need a lot of work, but you can get some help from trainers and/or rescue groups. Don't surrender your dog to a kill-shelter if you can't resolve this problem, contact your local JRT or small dog no-kill rescue. I'm sure she could find a good one-dog home with more experienced owners if you cannot handle this.