Octoberrain, there is a councilling page in my local magazine, and youd be surprised by the number of mums that have this problem. because you have always rescued your children from their own stupidity, they have never learnt to stand on their own two feet, which is why now that you are trying to make them they are resisting. (a bit like when you first teach a toddler that they cant have candy from the shop every time you go...they always start off with a tantrum, and it will escalate until they realise it just doesnt work).
when your daughter calls, just tell her that you are happy to listen to her venting, but you wont be part of the solution. she has to come up with that, and put it into action, all on her lonesome. tell her its an early xmas gift from you to her. (people love receiving gifts...lol) you might also want to tell her how much you would love it, if she would just call and say hi mum, how are you? and not always call because she needs help. (this would be true to your son as well). i think acknowledging that you have not always been there because of your addict son would help too. tell her that you love her, but you have your own life to lead and your off to jump out of a plane.
as for your husband, maybe he is just sick of hearing about all of this stuff too. and he has learnt to just switch off knowing that they will eventually work it out. go and have some fun and some you time...you deserve it!!!