If you think it will increase your income and try playing gambling to gain experience and stick to your promises, you don't need to tell him because most likely your husband's answer will not support you and will even disappoint you, but if you are aware and you have gone too far Please tell your husband immediately so that you don't fall into deep gambling
I have the feelings that the husband is reading this thread also unless if he is not a member of this forum, but then we have to face the truth as a community that practices just and right, and for that not telling the husband is a big mess waiting to happen, and if the husband later discovered that the wife is gambling secretly, it may not go down well with him also, and of that be the case, then we need to advice with rhe right set of advice and in my own opinion, is very inappropriate for spause to keep things away from each other, most especially things that involve high risk such as gambling.
If you say the woman should keep this away from the husband, it will eventually results into issues along the way most especially, if and when there are cases as regards to addictions and problematic gambling issues that requires the help of a third-party such as the husband.