Dearheart, I'm going to tell you what it did to MY son.
My ex husband (now deceased) was ok with my son until he became a teenager and was trying to spread his wings. My husband was great with my son for awhile because my son was an ACE pitcher in baseball in his senior year. He won every game he pitched in, and had the best curve balls, sliders, etc., than anyone in their league. Everyone wondered where our team got this "boy wonder" and he always made the newspapers. Well, that stroked my husband's ego, you see. HIS SON was an ace pitcher!! Wow -- HIS SON!!! You would have thought that HE had done the pitching!!!
After a a month of pitching, my son's arm started hurting -- bad sign. We took him to the best doctor in the area for sports injuries. Bad news -- he needed surgery. He had surgery -- and found out he was BORN with NO CARTILAGE in that shoulder!!! So that ended his pitching career. And that ended the pride my husband had in my son.
From then on my son could do nothing right. Nothing. Of course my son was devastated he couldn't pitch anymore as that was his dream. His grades began to fall -- my husband went into a rage. They would fight -- and my husband would blacken my son's eye!!! This would happen when I was at work, or I would have probably shot him with my 12 gauge shotgun!!! They began arguing all the time - even when I was home, and i'd have to get between them. My son never did anything right according to my husband, and it could be just LITTLE things. ------
There's no point in going any further with this -- you get the picture. My son turned to alcohol for solace. He became an alcoholic. He drank for over 20 years because he could never measure up to what his father wanted. All he wanted was his fathers love. Just 2 months ago, we were called at 3:30am to the hospital and told to get there ASAP as my son was dying due to liver failure. When we got there, he was yellow as a cab. He spent 2 months in the hospital Critical Care unit and also in a physical rehab facility. I just brought him home to care for him. We don't know how long he'll live as his liver isn't workiing 100%. It's at about 20% so the prognosis isn't great.
You have GOT to do something. Whether you go to counseliing for both of you or just your son -- that would be good, but it will NOT stop your husband from degrading your son.
Personally, knowing what I know now -- I'd leave. I'd get out before my son was damaged any more than he already is. That WILL still have an effect on him years later - and he'll need therapy in order to deal with it.
My prayers are with you. God bless and please take care. Hugs, Lee