KL, I can't even begin to imagine your pain. The people who did this to you are terrible, horrible, vile people, and they shouldn't get away with the trauma they put you through. Please don't let this break you.
The fact that you have managed to get this far speaks many volumes toward your inner strength. You survived the abuse, and now you need to stop punishing yourself. This was not your fault. It was never, ever, your fault. Even if you think in the slightest it ever was, please know...IT WAS NOT. You have nothing to be ashamed of. The only ones who should be ashamed are the sick twisted people who did this to you. But that doesn't change the hurt, I know. The damage was done long ago. You need to talk to people KL, and keep talking. And when you feel like you don't want to talk anymore you talk again.
Walk away from the bad things in your life and start living for you now. You have children who rely upon you now, KL. Show them you can be a better parent than yours were to you. Show your children that they can have a father who is there for them, and show them that you would never hurt them, and that there is still hope.
You know more than us if telling the mother of your children is best. If she will think less of you because of what happened, than perhaps she is not the one you should be with. It sounds to me like she may also have some issues if she is drinking that heavily. But If anything she may understand a lot more that you went through more than being hit, and it would explain a lot about your feelings of being detached and emotionless. I'll leave weighing the pros and cons to you. Consider the best and worst case scenario in telling her and determine what is worth doing. You need to be around supportive people who can help you through your struggle.
In my opinion (and I'm sure everyone else here as well), you have suffered enough, and it's your turn to be happy now. Please, please, please don't give up. Your children need you. You may think they don't or that you may not do any good but you still can. Please be there for them and you will see how your life can change for the better. Please keep talking to people, please keep sharing your thoughts, there are always people who will listen. Do what's right for you and your family.
Stop drinking, get rid of the drugs. I know you say they help dull the pain but how has that been working out for you? What do you want out of life? What do you want for yourself? Where do you want to see yourself in 10 years, or 5 years? What kind of person do you want to be and what do you have to do to get there? STRIVE to get there KL.
Don't let people tell you it can't happen. Don't let yourself doubt your abilities. Listen to this if nothing else. If you can make it to right now, this very moment, after everything you have been through in your life. You can do absolutely anything. I hope one day you will see that, because I can't imagine how difficult your journey must have been, but I can be very honored that you decided to share your story here, I know it wasn't easy, and I wish you and your family nothing but the absolute best which is what you deserve KL.