Help needed please(also posted on paralysis & senior board)

[Stormkat77]

A little history...
We have had Wicket since he was a pup. He was such a cute puppy and I think we let him get away with a bit too much and at about 2 years of age he started to get nippy. We took him to obedience classes, but without much luck. Fast forward several years to 2008 when he was paralyzed in the back legs. He was still nippy, but we could handle it. Within the next 2 years we built a house, moved and had a baby. Now, our son is 2 years old. Wicket does not like our son and we have had to go to great lengths to keep the 2 separate. In the past few months Wicket has become very anxious and will go through spells where he barks constantly. For instance, today he has barked for almost 3 hours. We had a trainer come out and I have been working with him, but it does not seem to be doing much to help him. I also have a prescription for him for Clomicalm, which I admit I give to him irregularly. In addition, he just had diarrhea for the past couple days. My husband has pretty much checked out of the situation, leaving me to deal with everything Wicket related.
I guess my question is, what would some of you do in this situation? We can't rehome him because he is an aggressive, paralyzed dog. I really don't want to have to make the decision to put him down as he was my first dog and I was super attached. On the other hand, we have totally had to modify our life to accommodate his paralysis and aggression. We aren't happy right now and I question his quality of life too. I have done the questionnaire about when it is time to euthanize, but I think I skew the answers based on my feelings. I am so upset about this and feel like no one else understands. I am sure many of you have faced tough decisions like this I had always got good advice when Wicket was first injured. Thanks in advance for your help.
Kathy