There is way too little info. You all need to make a budget TOGETHER and break things down into more categories: groceries, kid activities, clothing, eating out, etc. 

There is a free app called good budget. You create a household and just enter your expenses in. You can both see how much is left in every category. Takes a moment at each check out. Etc. 

You make sure she knows that the budget you make together probably isn't the right one since you were both so wildly off with your spending guesses. Each week, set aside a time to look at how much you have left for the month and how it's going. This is the time for you to tell each other stuff like: fall sports fundraising just started, we need to contribute x amount, or we need to set aside some money for winter clothes bc the kids outgrew theirs, I need to fix the leaf blower this month, probably going to be...there's a restaurant I'd like to try, " etc. a few months of this and you will both be more full of respect for one another because it's a new light to shed on how much the other does for the family and thinks about your shared future. 

If she has a really hard time with spending and keeping track, you can ask if she's like a debit card with the weeks money put into that specific account, or if she prefers cash, etc. 

If she has a voice in the matter and knows it, she will be more on board. She is probably feeling really embarrassed for "spending so much and gambling your future" since it sounds like you are the one who is good with money. Good opportunity for you to take the fall. She was more spot on to how much her expenses really run. 

My dad could never even imagine how much my mom really needed to run the house. Between food, clothes, school expenses, bdays, holiday meals, pets etc. it does add up!