Hi Aj
I don’t be***ve it is possible to move on as though nothing has happened as a great deal has happened.   It is important to gain from the knowledge and experience and not lose more than you have already lost.   Moving on with knowledge will make things different for you and that help you cope.  
Your husband tells ***s to protect his addiction and as time has gone on, his ***s would have become more and more fanciful.   I cannot tell you what to do but I think it is best to not trust anything he says because he cannot trust himself.
Every *** he has told to cover unacceptable behaviour has built upon a previous ***.   After years of ***** the CG(compulsive gambler) is so riddled with ***s that truth is totally lose – your husband’s ***s have become his truth and it is all he he remembers. It is the addiction at work which has drastically changed his reality to fit his personal perception and it is extremely sad for him as well as you.
We have discussed telling children in our Friends and Family topic forum (just below this forum), please have a look at it and perhaps write in it – you will be answered.   I think it would be better for you to gain as much knowledge as you can before you can make your informed decision for ‘your’ children.
Does your husband accept that he has a serious addiction?   Does he want to control his addiction and if so what has he done so far towards getting help for himself?
Your husband’s head is messed up but your marriage does not have to be.    In my opinion, it is better to sit tight and learn as much as you can, until you are ready to make ‘your’ informed decision on what you want to do with your life.   To do this you need to regain your confidence and self-esteem, which is in your power alone to do.   Your husband is like a 4th child.   For a long time you will have been bringing your ‘4’ children up and you
have managed because you are stronger than your husband, as you are not controlled by an addiction.  
Is your husband’s work ******* up in your businesses?   It is important for a CG to accept their debts from their behaviour and to rectify them without enablement from another.   Obviously if your husband is being paid out of your business this is more difficult.  
You are already doing well by removing your husband’s access to money. Cash to a CG is the same as giving an ********* a drink.   Unfortunately you cannot make your husband stop gambling – he ***** the right support and it is to be found on this site and in GA. Dedicated addiction counsellors and other CGs who are living their lives in control of their addiction will understand your husband and support him. 
It is important to realise that your husband’s addiction is not your fault and not his either.   Neither of you deserve what has happened to you.   It is ‘you’ that you can look after and it is ‘you’ that you need to look after.  Every day make sure you do something for yourself.
As Monique has said – anger is so understandable but it wears you out.   Don’t threaten your husband unless you are 100% sure that it is what you want.   His addiction is the master of manipulation and if you don’t carry out a threat the addiction sees it as a weakness and a green light to carry on.
It is not the professional way but many of us have separated the addiction from our loved one as a coping mechanism.   When you talk to your husband, it is good to imagine his addiction as a slavering beast in the corner waiting to leap out if you threaten it.   When the addiction sees anger, threats, pleading it comes between you and you and distorts what you say and the twisted rep***s you recieve are the addiction talking.   Keep that addiction in the corner, confuse it by not behaving as it expects.  It will always be looking for a reason to blame you.      
I will wait for your rep***s and then talk further