Basically in any case, lies will always be something that can reduce the level of trust, and in a household relationship it can be said that trust is one of the keys to a more harmonious relationship, especially if something you hide is an activity that as a whole or in general has a bad stigma in the eyes of society.
Although I understand that gambling responsibly may keep you safe and avoid various bad possibilities such as those experienced by addicted gamblers, it does not mean that it will completely make you not lose at all, in the sense that there will always be some money lost, meaning on the other hand there is an element that in the end or over time your wife will find out about something you are hiding because gambling involves money and in a household relationship finances are usually one and transparent, meaning your wife will definitely know that there is some money lost consistently, and this is where suspicion and arguments will begin.
Therefore, I think there is nothing wrong with being honest from the start, because even if for example now you succeed in hiding everything from your wife, it does not mean that your wife will not know forever, remember that you live under one roof.
Once you do get caught then there's no way on making it back once that trust will really shattered or be broken specially into your wife or husband.This is why it would really be better that you should really be that making yourself being mindful about those probabilities and this is why its not recommended that you would really be hiding up something from them as much as possible.
How i do wish up on a peaceful life with having no worries about particular things. If you do find yourself that being interested in gambling or betting then tell your wife about on what you are doing.
As long you do make yourself that being responsible on the way you do spend up money or finances with betting then it wont really be that issue but if you are showing up some signs that
you are doing something shit then it would be normal that they would really be making up those words which would really be against on what you are really that doing.
True, it can be said that trust is something that can be the key to a harmonious relationship as I said, and maybe you have often heard that honesty is more expensive than anything, because when someone no longer trusts you then they will lose interest in dealing with you, and of course that makes it quite difficult for you when you want to ask for help from that person because there will be a lot of doubts that grow in that person's mindset towards you.
On the other hand, as you said, it is very important to be aware of the possibilities that could happen someday due to the actions you take now, especially if you lie to the people closest to you where as I said before that you live under the same roof with them which in the end the act of hiding will be in vain. And when the story is different in the sense that if from the start you had told your wife about you being involved in gambling then surely your wife would at least help you to overcome everything especially when it turns out that you start to fall into an impulsive approach to gambling.