First of all, I just want to say, how wonderful I think it is that you rescued this little guy. Sammie hasn't bonded with humans like most yorkies because of his earlier life, and he has trust issues going on. I think, in general, most dogs do prefer other dogs to humans, but many yorkies seem to prefer humans. I think you're lucky that Sammie likes other dogs and I hope you can allow play dates with Bernie once a week or so. Some people will probably suggest you getting another dog, but there is no guarantee Sammie will bond with another dog like he's bonded with Bernie. Maybe Bernie is his soul mate!
You sound like a wonderful mommy!