My guy came to me in Jan 2112, at 15 months old. He has always like a lot of attention. Now close to 27 months old, he has become even more attention seeking. He does a lot of "nosing" things on the coffee table and does "scratching stretches" on furniture. He responds well to the no or uh oh...but not for long!!!! He likes me to chase him all over the house..many times a day! If I try to ignore him he does the little whine, and stares!! I take him on 2... 20-40 min walks a day. I have a large fenced yard...now with 17 in snow! He is very food responsive, but feed and treat games were either too easy or way to frustrating for him. He likes to eat his dinner from his Kong Toy!I give him cubes of frozen Greek Yogurt for treats.
He stayed with Foster Mom in Oct ( +3 dogs),and had many great chases with her latest Hav rescue...so I am thinking of adding another Hav guy. ( He is very social with people and all other dogs.
I guess I am worried that it might be a colossal mistake.
Lots of people have multiple Havs and thoroughly enjoy it. Most of the dogs seem to get along well. B-U-T, you should get another one for YOU, not for him. There are definitely trade-offs. They won't ALWAYS get along, he will have to share your time with another dog, and expenses and work load automatically double. The people who choose to have multiples mostly seem to think it is worth it, but you need to think it out.
As far as the immediate problem, for Bax's own sake, he needs to learn to occupy himself at least some of the time too. You got him older, so it may take a little more work. But I would get him some great chew things, like moose antlers, flavored Nylabones... whatever he likes, and a few toys like Skinneze or squeaky balls. Then I would start purposely leaving him, either in an ex-pen or gated into an area that he can't get to you. Do it in a kind but matter of fact way. DON'T feel sorry for him. Then start leaving him there for slowly but progressively longer periods. Start really short, like 5 minutes and work up from there.
Another thing to work on is to teach him "place". This is a spot that you choose, that is the place he needs to go and hang out until you release him. It could be an open crate, a dog bed or even an old folded blanket on the floor. Again, start with very short periods at first. This one can be as little as 30 or even 15 seconds to start with. The point is for him to learn that he MUST stay there until you tell him it's OK to leave.
I would do these things with him whether you decide to get another dog or not. They are just things a dog needs to learn. What if you got another dog and that dog got sick and needed to be hospitalized? Bax might be beside himself hif he didn't already know how to entertain himself when necessary.