I have two Male dog, Max is a 10year old Shih Tzu and Stitch is a 1 year old Maltese/Shih Tzu. When i first brought home Stitch Max was a bit hesitate to this new puppy on his territory. Max was also a very laid back lazy dog, never wanted to play, just sat on the couch all day long. Since we brought home Stitch Max is alot more active and playful he seems alot happier.
My parents didnt want to bring home another dog incase it would upset Max but would completely agree now that Max seems alot happier. If your thinking about bringing home another dog my advice would be do it, it takes some time for your dog to get used to the new puppy and will make sure hes still boss but its really given Max a happier life!
Hope this has helped anyone thinking about getting another dog!
Jean