Should I tell my husband that I gave my mother an amount of money that was allocated for our honeymoon without his knowledge, and what are the consequences of that?

A wife is not permitted to dispose of her husband's property except with his permission. An exception to this is a small amount that is customarily overlooked, provided she has his general permission. If a woman gives charity from her husband's money without his permission, she receives half the reward, and her husband receives the other half. The wife must repent to Allah and return what she took from her husband's money without his knowledge. She can deliver the money to him by any suitable means without informing him.