I am bringing up my ‘F&F Cycle’ thread for you.  Your feelings of desperation and then hope and then desperation are common for the F&F – they are feelings determined by the addiction of another and I hope the thread explains why.
Although it is not recognized professionally the following is a coping method that many of us have used at the beginning of our recovery to help us cope.
Imagine your husband’s addiction as a slavering beast in the corner of the room.    As long as you keep your cool and don’t threaten that addiction it stays quiet, although it never sleeps.
Your husband is controlled by the addiction to gamble but you are not.   When you threaten that addiction, it comes between you and controls the conversation or argument.   It is the master of threats and manipulation and you are not.   Once it is between you, you will only hear the addiction speak and because it only knows lies and deceit, it will seek to make you feel blame and demoralize you.   When you speak the addiction distorts your words and your husband cannot comprehend your meaning.  
I think it is good, although difficult, to not ‘try’ and believe the CG because in doing so you become receptive.   If you can stand back a bit and listen to what he is saying, it becomes easier not get caught up in an argument that has no point apart from making you feel less in control.   Once you begin to try and put your side the addiction has something to get its teeth into.  
Please start believing, knowing that you are not responsibly for your husband’s addiction.   Do things that please ‘you’ that are not associated with his addiction.  See friends, alter the furniture arrangements, have a massage – something that pleases you, perhaps an old hobby that you stopped because the addiction was in your life.  Rebuild your confidence and self-esteem – don’t let the addiction take you down any further with it.
If your husband does go to GA, join this site or see a dedicated counsellor the fact that you are not part of the wreckage of his addiction will help him.   If we do not recover then we are still victims of the addiction and as victims we are powerless.   Of course it is alright to feel anger – it is a natural reaction to your experience but your husband has not deliberately hurt you.
If you look after you, you will feel less tired and more able to be there for him if and when he changes.  
It will be a long time before you can trust your husband – he cannot trust himself so why should you?   The forum will be here for you whenever you want it.
I would not be writing here if I did not know this addiction can be controlled but I know we cannot control it.  You can only control yourself and to do that you have to take back your life and deny the addiction its power over you.  
I will be back next week and hope to read an update from you