Hi Tanya
I hope that by talking, one of things I can help you feel stronger with is your feeling of rejection.   Your partner doesn’t deliberately hurt you.   His addiction renders him emotionally immature, lacking empathy, reason and logic.
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 forever watchful.
Your husband is controlled by that addiction 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 ***s 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.  
My CG explained it to me by saying that when I told him (for instance) that if he didn’t *** but lived honestly he would be happy, his addiction was distorting his mind convincing him that I was ***** because he truly be***ved that he was unlovable, worthless and a failure – he was lost and fought back because he didn’t have any other coping mechanism.   The addiction is all about failure for the CG – they cannot win gambling because they cannot walk away.  Squash you and the addiction wins – but however much your husband convinces you that he is in control – he is not.
It is incredibly difficult but if you be***ve what your CG is saying, you become more receptive to his addiction.   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.  
Getting on with your own life is easy to say and difficult to do but it does work, it will support your partner and hopefully make you feel less tired.   Doing something for yourself is often completely overlooked by those who have been living with the addiction to gamble.   Your husband’s addiction will probably have been filling your mind every minute of the day.   Try and find something that you will enjoy, something that has got nothing whatsoever to do with gambling.   A massage, a new hair-style, a hobby – forgotten because of the addiction but previously enjoyed, going out with a friend, anything that takes your mind out of itself for sometime each day.  
I am glad you are going to Gamanon – it is good to physically meet with people who ‘understand’ you as nobody else can.   In my view, it is great to use this medium plus Gamanon.
There is a load more to be said but I will leave it there for now.  You have done incredibly well writing your first post, I know the first post is the hardest.
We hold our hands out in the dark for so long, groping for understanding, I remember how amazing it was to find a hand in mine and to know I was among those who understood.
Speak soon
Happy is she or he who can tell you ‘Today I’ve lived’.