Hi…it is the worse thing to experience the torture of loving a partner,son etc who is an addict because i do get where you are coming from you love them want to support them and it is soul destroying however when he is abusing you and when he isnt trying to get help there has to b a point that you step back and put the focus on your own life because you cannot change them the only person you can change is yourself and it doesnt sound like it is a great environment for your son to grow up in..you say they adore each other but really do you want him scarred for life if he is enduring abuse and being left for periods of time while he goes and scores because that in and out of his life isnt fair on him..ive been thru all of this and have children and have had the clean times and the times in active addiction with my partner but never would i have had him kicking shit out of me..im not saying he couldnt be abusive because he could the addiction brought me to my knees but trust me he has to be actively trying to get help and you need to get to a point where you step back or yes this will continue and yes you will be muggin yourself off.
Hope you can get the courage to put urself first..and find some inner peace soon