Heartbroken by breakdown of marriage

My husband has adhd.  Our relationship has always been difficult, but after the birth of our first child, I just couldnt take it anymore and when my son was 6 month old I left him.  In the beginning of our relationship he was the most amazing person I ever met.  He was so kind, considerate, generous and I couldnt believe how much he loved me and I fell in love with him, although he never believed that I ever loved him.  Everything progressed really quick in our relationship, he was desperate to get me moved in and married, so we married after 18 months.  Thinking back now, I could probably see some signs but I put it down to being silly when drunk etc..  Basically as soon as we were married, he totally changed.  He didnt seem to care about my feelings and would just go out and get drunk and stay in bed all the next day and didnt seem to care about me.  When we would go out, he would totally embarrass me in front of everyone saying things about me to other people and would fall out with me over stupid things.  He decided to stop drinking and take up cycling.  So he basically replaced the obsession with going and drinking with cycling.  He would cycle all weekend and by this time I was pregnant.  Even If I was ill in bed with the pregnancy, he would get so angry as this would stop him from getting out on his bike, I would tell him just to go, so I could get peace.  He started getting really angry about things and a couple of times when I was pregnant he acted violent towards me.  I left him several times during my pregnancy, but I always went back to try and make things work.  I failed to mention he had loads of debt when we married that he never told me about and every month I couldnt understand why he was broke, but he was paying back interest on all the debts. 

Once I had the baby, he had 5 weeks off work and was really good, as I think the baby was a novelty.  Once he was back at work, things became difficult.  He is so selfish, he just wants to do his own thing and in the end I couldnt even get out the house to go to the gym, as he couldnt cope with looking after our son for a couple of hours.  Two months after my son was born, he gave up the cycling and went back onto drinking.  He would leave me in ill with the baby and go out drinking and this was his priority, he didnt seem to care.  Our first anniversary, he went out all weekend and left me ill with an 8 week old baby and I didnt want to call on any of my family as I didnt want to admit what he had done and I was too ill to say anything about it.  He continued to drink and be selfish and became violent with me whilst I was holding my son and I finally left for good.  That was 5 months ago and I still find it hard coming to terms with everything that has happened in such a short period of time and that really isnt the half of it.  He doesnt want to see our son at the weekends as he is back obsessing about his cyling once more and by his admissions is too busy to take him at weekends, so he is not seeing him at all at the moment.  His parents dont help as they stick up for him and accept everything he does.  Its really frustrating.  I didnt leave him because he was ADHD, I left because I didnt want to keep being a doormat and live a lonely, non-existent life.  I do still love my husband, but I just cant be with him anymore and it breaks my heart.  He doesnt seem to think he has done any wrong and seems to blame me for everything that has went wrong in his life.  He is very bitter that I left and I guess his way of dealing with it to act like he doesnt care about our son, as he knows this will hurt me.  I tried so hard to make our marriage work and I am left exhausted by all of this.  Any encouragement would help.