hi welcome, i agree with impurffect, there is nothing you can do to help him or get him to help himself. he has to want it for himself. i'm a recovering addict married but seperated after 21yrs of trying to help and sticking by my husband which by the way, it almost literally drove me insane. many days i wanted to drive off a cliff somewhere but i too had kids (7) who needed me, so i do understand how you feel and i'm truly sorry.
take the focus off him, allow him to suffer the consequences of his action and pray that he finds his bottom soon.
you say you'd be lost without your husband but is he really there when he's there? its the drugs, this behavior that you described above, is just how addicts are. read the stickies at the top of the forum page, keep reading and keep posting. i agree that meeting are very helpful for you. the way you are feeling right now is also common for those who loves an addict and we need to help too.
i think by coming here and reaching out, you are well on your way. its not easy but one day at a time, it will get better even if he decides he's not quite ready to yet. i'll say a special prayer for you and your family.