Behavior Problems of our Lab

Question
We have a 4-year-old chocolate lab and have raised him since he was 6wks old. He has finally calmed down,but has always has seperation disorder.I am an at home mom so he's not alone that often.We have video taped him and he runs around crying and used to distroy things(blinds,door frames etc.)My husband brought in another dog this fall and it too is a rather large dog, this seemed to help to calm him down,but it has proven too much for me with 3 active boys and so the new puppy is going to a family friend.I am worried this is going to affect our Lab.He is also very aggersive in tempermaent towards strangers and very protective at home,but handles himself just fine at parks;although he will not let anyone pet him,he chooses to be stuck-up.At home we do not dare leave him off the lease because he takes off and we have to chase him down.He loves the children, but has a superiority with them as well.He will fetch a ball everytime,but will only let you have it when he is good and ready.The only one in the family he obeys is me and uaually my husband. I should mention that he other puppy who it 8mo old gives us no trouble, he is a shepard-collie mix, never leaves the yard doesn't require a leash and is very loyal and submissive,and I trained them both the exact way.(I really hate to see the puppy go.) I love our Lab,both dogs are indoor dogs and treated as part of the family. I should mention that our Lab is not fixed and where told that could help. My oldest son who is 11 and I are the care givers.Please help!!!!!! My husband and I are afraid we are giving away the wrong dog,but we do love him.He has gotten the reputation amoung my family(mother,father,brothers) as the "jerk" and I only have one brother that will come over and attend to him when we leave town.Please HELP!!! Thank you.

Answer
Some Labs can very dominating.  From some of the stuff I read, I suspect some ''experts'' have never encountered the likes of him.  Neutering him would help, but will not solve the problem.  You may have taught him to sit when you say so, but you have not taught him you are top dog.  That will be difficult at 4 years old.  It would be too much to try to explain how here.  You need a good trainer or a good book.  There are plenty of poor ones of both around.  The one thing you can count on is How to be Your Dog's Best Friend by the Monks of new Skete.  See http://www.dogsbestfriend.com/