I honestly think yorkies are individuals. Some like to be singletons, some love being part of a pack. My little man loves playing with other dogs at dog parks and meetups, but I think it will drive him up the wall if I ever add another. I honestly am not sure about that since I've never brought another dog into my home at all. My friend fostered a yorkie and her yorkie was so completely miserable! She loves her best friend (my dog) but I think she also likes that at the end of the day, he goes home and she doesn't have to share her mommy. She's younger than mine too, so it's not like she's lived as a singleton for years and years and just needed to get use to it.
You'll just have to see what your little man likes and dislikes. After a while, you'll know.
