Putting on a front gnaws away at your personality and ruins your self-esteem and it obviously isn’t good. If it was me I would tell the 2 people you trusted before because you need support and freedom to relax without a mask. Secrecy is exactly what a CG wants if he is to keep the door open for his addiction.
Your husband has asked you to help him which is good and getting a block on the internet is a step in the right direction. In my view, however, he should take responsibility and put the block on himself.
What is he doing to make things different this time Ivy? Is he going to GA, is he seeking counselling, is he prepared to talk to our helpline or join our CG groups?
Your words to your husband were fair and did not threaten your marriage – you told him you don’t know if you can continue which means he has the choice to put this lapse behind him and live gamble-free or carry on and wreck his marriage.