Dogs are remarkable at sorting out politics. We had a Shepherd, named Fritz, who was great with other dogs. Part of his demeanor stems from the fact that we got him while living in England. We brought him home at 6 weeks of age and took him to the park often. In the UK, there are few leash laws, dogs a free to run in most parks and socialize. Fritz was 105# as well, and slept on my daughters bed for the first five years of her life. He played equally well with Yorkshire Terriers as he did with larger Shepherds.
After two years, you should have a pretty good feel for your dogs temperment. I would be inclined to add a second dog. Close supervision is key though. they will quickly sort out heirarchy and establish a relationship. If you can spend significant time with both dogs in a fun environment, together, the new-comer will be associated with positive reinforcement. If not, you run the risk of an adversarial relationship where your Shepherd feels threatend and will instinctively try to enforce his 'Alpha' position. You didn't mention sex. Males are typically more territorial, they will protect thier turf if they feel threatend. Females tend to pay more attention to the pack. Consider your family as a part of the pack in this situation.
Good luck.
EDIT - I see you refered to your dog as a he. I think the introduction into the home will be key. Perhaps establish a space that is his own, and a space that will be that of the new dog.
Last edited by Trapps; 09/26/03 02:24 PM.
