Well, your first order of business is to address the infidelity. Altering a check you wrote and signed is an unfaithful, disloyal act. Your second order of business is to show her a budget that pays the bills, feeds the kids, saves for the future, etc and explain to her if she wants a bigger budget she needs to go back to work. Period. Your wife isn't bad about money. She's bored and unfaithful, and passes time by spending money. Good luck.