We got Jack, a 4-year-old Shih Tzu/Terrier mix from a shelter to be a companion for my wife when she was disabled, and he has done a great job. But she is now able to go back to work, and Jack is getting lonely being by himself all day. We're thinking about getting a companion dog for Jack and are wondering what we should do to make sure they will be a good match. I'm thinking a female dog, because Jack has gotten along well with our daughter's female miniature dachshund, and my brother's female dachshund. My wife wants a second dog that is smaller than Jack (he's about 17 pounds). Any suggestions?

I would suggest getting yourself back to the shelter! I am sure there is a little girl there just waiting for you to come along, GOOD LUCK!