I don't know why you're hiding from your wife that you like to gamble. Personally, I think that this kind of secrets negatively affect the trust of spouses. Just imagine what can happen when your wife finds out about your secrets, and you find out about her secrets. I don't think it would do any good. I told my wife about gambling before I married her, so it makes no sense for me to hide from her when I want to gamble. She understands my hobbies perfectly well and tries to stay out of it.
Exactly since if he's just open to whatever activity he participate then for sure that her wife would understand about what he do. If he's unfortunate that her wife doesn't understand about what he do since what she think is his husband is just wasting their money then maybe its good to make her understand the whole situation and make her see that you are just relieving your stress from heavy days of work. For sure everything will be settle on proper discussion so we should not hide any secrets to our wife so that there's no relationship will get destroyed. Sometimes Its hard to admit that we are participating on gambling activities since there are people always have negative impression about it but for sure they will get used to it once they see that you are fine even if you gamble on some occassions.