Since no one stated the obvious: OP should stop gambling, too.
You're right. I should stop. Or at least not encourage it.
I have never gambled on my own. If I'm at a casino, I gamble. If I'm not, I don't. I don't look for it. DH does. But if we have a little extra to have fun with, we go. Gambling is all around me. It's our fun. I even used to work as a dealer.
DH has been golden when it comes to giving me his weekly share of the finances. It's when he digs for the money that ends up hurting. He does have a problem. The positive thing is that his actions now are nothing compared to before. The negative is that he still does it. He found a way to pay for his cash advance, so issue solved for now. I dread the day he does it again.
Think of gambling as alcoholism. For most people it's nice to have a gamble every now and then, but they will not miss it when they go without it for weeks or months.
In your DH's case, it has become an addiction. And, just like with alcohol, you can't have 'just one gamble'. It always progresses into more. The consequences are just as severe: (financial) ruin, lost relationships, etc.
So he needs to quit gambling altogether, and frankly so should you. If we were talking alcohol, you would not have a drink in front of him, so don't do the same with gambling.
And, as it is a true addiction and disease, seek help. He may not be there yet, as acknowledging is the first step of the solution, but keep bringing it up with him, he may start to realize it.
I like to gamble. I even have the Total Rewards Visa so I can save up extra comps for meals, etc. for when I go. However, I am in complete control of myself. I never spend money needed for bills or savings and I stop when I know it's time to stop. It sounds like your husband has a very addictive personality and he's become addicted to the dopamine rush that comes from gambling. It's basically a drug dependency on the chemicals being produced by his brain. The best way to handle it is to redirect him toward something else that can give him that kind of rush. One good option would be sports and exercise. Those kinds of activities produce dopamine, appeal to people with competitive energies, and produce positive physical results.
Once you deal with the addiction, then you can focus on the debt. Start by writing out a list of everyone you owe. Some of your gambling debt may be on credit cards . You may have overdrafted bank accounts. Or, you may even owe casinos. Put all the debts you can think of on the list. If you learn of new gambling debts, add them to the list. The key is to know who and how much you owe so you can take action.
In the situation you and your husband are finding yourselves in, it might be best to seek help. http://www.ncpgambling.org/i4a/pages/index.cfm?pageid=3311 has information, and perhaps you should both put your names on the self exclusion lists until you can find a healthy way to get your finances, relationship and addictions in order. I wish you the best of luck. http://www.gamblersanonymous.org/ga/ may also help.