Ok - this site is already helpful to me! Thank you all!
To doggonecarl: This was not a gradual change. He will freely admit that he is addicted to pot and that he thinks it is a substitute for alcohol. Before we were married he cut way back on drinking though and I never remember these mood shifts. The chronic all day smoking started about 5 years ago and he has every excuse in the book. The problem is that I won't give him more money, not that he can't look for work because he can't pass a drug test. The problem is I won't leave him alone (his teeth are falling apart) not that he spend the dental money on pot, etc.
To Dee74: "I think the main question here should be - what exactly are you prepared to put up with for you and your kids?" is exactly where I am at now. Even though I would like to keep the family intact, his behavior and my actions as a result (working two jobs, crabbiness, exhaustion, poor health, lack of sleep on and on) is driving me to realize that most things would be better than this. Also seeing my 7 year old daughter crying under the computer desk is a real eye opener, but worse is that she forgave him (he often turns into really nice Daddy after these events) and I realize that she is accepting this as normal. I have to set a better example and like it or not, me being here is allowing it to continue (enabling?). He gains a lot of gifts by me being here that he is so not thankful for (food, I keep the kids going in some semblance of normal family) so he does not need to face the consequences. He wouldn't be able to support even himself if I left tomorrow.
I sound so angry and realize that I am.
Thank you again all.