sounds like he has won. he has you convinced that you cannot do anything - that you have to just stay there and be a punching bag. i dont believe that there is no way you can get out - there are ways - there are shelters - there is help, as your friend has explained to you. yes it may be inconvenient and it may not be luxiourous but sometimes we have to lower our standards of living for a little while if we want to reclaim our lives.
you have two daughters that you use as an excuse as to why you cannot leave - what are you telling them and teaching them? by this time they have it ingrained in their psychie that this is how a woman should expect a man to act - which means that they have a good chance of ending up in the same kind of relationship. if you want to change this then you get out and you get those girls out of there - if he hasnt started beating on them yet then chances are he will before its over.
personally i dont think that once a man has hit you that it will stop. i'm sure there must be some success stories out there but this behavior isnt just drug addiction - this is a man who feels he has the right to hit people to get what he wants. dont think i'm just preaching at you - i've been through the abuse with two relationships - both ended up trying to kill me, one by choking me and one by a gun (lucky for me he was too drunk to be able to aim straight.) it doesnt end until you end it.
if you wont get out for yourself then get out for your daughters.