I don't see any problem there. Its true that we shouldn't gambling in front of children as it may effect them badly. But when its comes to mature people like you and your wife, there's nothing wrong until both of you guys can control yourselves, follow the discipline as well as able to manage economical status and become so responsible as gambler. Nobody need to quit, just mainly focus on primary income source and do gambling less or stay within limit. Don't spoil family moments , only gambling when get free time or children aren't around you.if you guys can't handle and worry about Ensure the healthy environment for children, then both can quit gambling together, otherwise there'll be a quarrel between you about this matter. So that is my suggestion
I do not think that there is any couple who would succeed in hiding their favorite hobby of gambling, especially if they practice it inside the home. I can't imagine any hypothesis that would actually work.
Perhaps theoretically, it is possible with zero probability that coincidences will not occur and the children will not notice anything. I find this to be a very difficult hypothesis to actually be true.
I also do not believe that it is a healthy environment for raising children to have anyone gamble, whether it is one or both parents. At least only one of them should love gambling so that the other party can find a balance, because there is generally no problem with one or both of them practicing their hobby only during the period when the children are away from home and at long intervals, that is, not every day.