Yes, he has tried completely ignoring him. That does not seem to work.
No, he has only periodically given him treats and gone on walks.
He is jumpy when it comes to unexpected loud noises or movements. Overall, he is not a nervous dog. He is very high energy, though, and is a runner if he gets loose. He thinks it is play to be pursued.
Robbie has gone to a doggie day care facility regularly for several years. He is a happy, sociable, an very well-liked dog. He loves the men working there. He especially likes kids!
There's actually a couple things we can try...
First, there are a couple over-the-counter products you can try to help ease his anxiety:
Melantonin is an over-the-counter drug that can be used to treat some anxiety issues in dogs. The dose you would give would be up to 3 mg given orally whenever necessary up to every 8 hours. More information can be found here: http://www.petplace.com/drug-library/melatonin-melatonex/page1.aspx , which includes risks, warning signs to watch out for and other bits of useful information.
Try a DAP collar. These are collars that are impregnated with a man-made version of the dog appeasing pheromone, which is a pheromone that nursing bitches give off to their pups to help them feel calm and secure. It's something that humans can't smell, but it has an amazing effect on dogs with anxiety and other issues. Although you can find them at your vet's office..you can also find them online at places like Amazon.com and Ebay for much cheaper. Just make sure they're DAP brand, as they seem to work better than some other versions.
And I would have your boyfriend do everything for Robbie from now on. If Robbie needs to go outside to the bathroom...your boyfriend lets him out. He walks him, feeds him, waters him and does absolutely everything for him. I know it will be hard for you because you and Robbie have been a team for so long...but you're going to have to remove yourself from the situation when Robbie needs something.
You could also consider having your boyfriend take Robbie to a basic obedience class...not because you want him to learn to sit/stay (because I'm sure he already knows that), but because this will build the bond between your boyfriend and Robbie. Terriers form relationships while working...and this class will be working for Robbie.
Over time...Robbie will realize that good things come from your boyfriend and will be less timid around him.
I hope this helps.
Thank you for your prompt and caring reponses!
I love all of your ideas, and many are new and interesting to me. I'll share them with my boyfriend. I especially am intrigued by having him do all of the care for Robbie.Right now that looks like the most feasible to start.
You have encouraged me a great deal.
Thank you so much!