insecure dog

Question
I have 2 dogs, a 3 year old Cairn Terrier and a 22 month old terrier mix from a rescue.  Both are males and both are altered.  I have had them both since they were 6-8 weeks old.  They have been through obedience classes and are well behaved and well trained.  My problem is with the rescue dog.  He is incredibly insecure.  He is prone to submissive urination if I raise my voice or if I move to quickly around him.  He is completely fixated on me.  He will sit at my feet and stare at me for up to an hour.  If I ignore him he will usually go to his kennel or lay down at my feet.  The worst part of his behavior is that he urinates in the house when I leave if he is not confined either in his kennel or in the kitchen with a gate.  I exercise them both daily by taking them for a walk in the evening - usually a mile.  The rescue never eliminates or marks along the walk while the Cairn marks everything he can.  Lately, the rescue has taken to urinating on the Cairn's dog bed - but never in front of me.  I have noticed that it is typically after I go to bed - they do not sleep with me nor do I want them to.  They both have dog beds and kennels.  I also have a doggy door that leads out to the yard. When I am home - the rescue usually avails himself to the yard through the doggy door when he has to eliminate.  For a while I only had one dog bed and the Cairn typically dominated it.  If the rescue comes up to the bed while the Cairn is in it, the Cairn typically will give it up and on rare occasions share it.  I thought this might be the reason the rescue was urinating on it so I got another bed and put them side by side - now he urinates on both beds - but never in my presence.  They never exhibit aggressive behavior toward one another.  They do play often and well together.  The rescue does not seem to like toys all that much.  He was very destructive as a puppy - especially if left unattended - clothes, shoes, furniture, pillows were all fair game.  Fortunately he is past that behavior.  He is not aggressive around other dogs and will typically stay at my feet when other dogs are around while the Cairn is happy and playful with all dogs.  The rescue does not play with dogs other than the Cairn.  I do not take them to the dog park because it seems to stress the rescue out too much and he is prone to caprophagia.  The rescue was diagnosed with skin allergies at a young age - he is on 12mgs. of Benadryl twice/day otherwise he will scratch himself around his mouth until he bleeds.  Is it time for doggy prozac?  I am at my witts end.  I would like to be able to leave them both without having everything in my house urinated on while I am gone.  I know it is the rescue doing it because I can confine him during the day and leave the Cairn out and there are no signs of urination.  I got the rescue so the Cairn would have a companion while I was at work - now I feel my attempts at companionship are not working since I have to keep the rescue confined during the day.  I am not giving up on either one - I will do anything and everything you tell me to do. I want to instill confidence in the rescue and help him be happy and well adjusted.

Answer
You have had this "rescue" from 8 weeks of age!! This by your own description at the top of your post!  Why do you call him "the rescue"??

Obtaining one dog for the companionship and entertainment of another is not acceptable.  Your second dog (I will call him "TWO") is reacting to your unspoken emotional distance.  He is psychologically subordinated, confused, stressed and unhappy.  IF you have had him since the age of 8 weeks, THIS IS YOUR FAULT.  You have absolutely no evidence that TWO is the marking culprit; the fact that there is no urine present when he is crated while your "Cairn" is not is not demonstrable evidence.  The Cairn may very well be marking when TWO is out.  Moreover, the Cairn is clearly following your lead and TWO is being emotionally bullied by both of you. This is shameful.  If you want TWO to feel confident and happy and well adjusted, you need to spend time with him AWAY from the other dog.  it's a bit late, considering you've had him since infancy, but better late than never.  Learn about positive reinforcement training, take TWO into a room without the Cairn, teach him every day in short intervals ONE solid behavior he can offer 100% of the time.  Do NOT use a clicker (since he is sound sensitive); instead, use a visual signal (put your finger to your nose).  learn about positive reinforcement training by reading Karen Pryor's web site and her book, "Don't Shoot the Dog", as well as Patricia McConnell Ph.D.'s book on the subject, both available from amazon.  Give TWO at least four weeks to learn this behavior. DO NOT LOSE YOUR PATIENCE.  I suspect you have lost your patience with TWO and he may be a "cinderella", not acceptable.  STOP seeing him as a PROBLEM and start seeing him as a dog that is desperately trying to BELONG (marking both beds, if in fact HE IS the culprit, and slavishly sitting at your feet, watching your every move for some sign of what to do next).  TEACH HIM how to please you and interact with him BY HIMSELF; take him for 1/2 mile walk alone, if you must.  Somewhere along the line, he's gotten the clear signal that he's not even "number TWO".  Also: FIND ANOTHER VETERINARIAN!  Benadryl is not a drug one gives any dog for any length of time.  That Vet is AWFUL!  His food allergies can be successfully cured by CHANGING HIS DIET.  There is a plethora of dog food available now, both prescription and non-prescription, for dogs allergic to the additives found in most commercial foods.  If TWO is suffering from a poor diet, so is your other dog.  Improve the quality of the food you offer, pay individual attention to TWO, appreciate him for the unique and loving dog that he is, teach him how to please you, and STOP thinking of him as a "problem".