What should I do with my wife who borrows money from some of my acquaintances without my knowledge, and I have three children with her?

The wife is financially independent, so she may borrow money without her husband's permission. He is not obligated to pay her debt unless he volunteers to do so, or if her debt resulted from his failure to provide the obligatory maintenance. The husband can advise his wife and remind her of texts warning against debt, such as the Prophet's (peace be upon him) saying: "O Allah, I seek refuge in You from sin and debt," and his saying: "The soul of the believer is suspended by his debt until it is paid off."