I have proof that my wife often secretly gives money to my grandmother

I was really sad because my first wife laid her knees over my face, lying like that.

I'm 40 years old, my wife is less than 5 years old, I have two children. We had houses and our economy was not abundant, but it was not bad. I am very clear about money. Previously, the money paid for both sides of my family and my husband and I were both fair and public. Recently my wife has been stealthily giving money to the foreign currency without telling me. I don't regret what my wife did but at least she had to say. Last time I discovered and had enough evidence but did not want to say, then there was a 2nd, 3rd time, the next time I also have enough evidence. What I have to do? Hope you read please help me.

Tung