You're getting a lot of bad as well as good advice here. First, as a retired, CFP, we don't have all the information here. How much is "a lot of money?" Is it $100,000, $300,000, $500,000, $3,000,000?
How much do you make? How much does she make? What are your goals?
Respectfully, you sound immature about money. Don't take that personally. The vast majority of people don't know how to talk about money.
1. Big decisions about money should be joint decisions. Big is a relative term. What's big to a couple making $30k is going to be different from a couple making $300k.
2. Each person should be able to buy whatever they want without consulting with the other spouse, subject to some reasonable constraints as to the total amount spent... $100, $500, $1,000, $5,000.... It doesn't need to be exact. Of course, the amount depends on the personal situation and what each party desires. Some people simply don't care about financial decisions as long as their needs are met.
3. The fact that you got into an argument over what to do with MORE money indicates some insecurity and immaturity on your part. More money for either of you should be a good thing in your life.
If this is a large amount of money, I'd suggest that you and your wife should see a financial counselor. You don't necessarily need financial planning at this point, but you both need to develop a healthier attitude towards money. Don't get me wrong.... virtually everyone needs healthier attitudes towards money. I wrote an entire book on this years ago and then ghost wrote a similar book for some of the top financial planners in America.
It's not about where the money is... joint or separate... it's how you jointly use the money to achieve your mutual goals in life.