if you really want to stop gambling it must have a strong belief from within you because it will be difficult if it becomes an addiction and should be supported also from the family.
To quit gambling is like a death to the gambling addict because they cannot live without gambling as they have made it as a source of income. they only possible way that the gambler can adopt to leave his gambling is to find something more interesting for himself other than gambling. If he cant find something more interesting than gambling, then he will continue with gambling for the rest of his life.
I think I agree with every single fact that you have discussed in your comment because gamblers cant leave gambling if they wouldnt find anything more fruitful to them rather than gambling like you said. Also, one more thing that I can think off for which I think gambler will leave the gambling is the financial crisis on him because when he would be having no money to play, he will automatically leave it.