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What will be your reaction?
Hmmm, I will request for an annulment immediately.
I mean if your wife is a gambling addict then that might be the reason why your life could be miserable, and worst, she might spend the money that you're giving to her like what the OP has shared.
Change? Maybe if your love for her is way important than those secrets, her gambling addiction, the amount of money that she spent secretly then you might still accept her and expect to change, but most will not do that especially if the amount of money that the wife used is too much.
Overall, this is a subjective matter, and it will also depend on the amount of money that she spent in gambling.