My wife is an impulsive buyer and spends a lot of money without thinking twice. Am afraid we are not saving enough. How do I explain her?

Have a serious conversation with your wife. It's difficult to have financial issues in the family. I can see that you are capable of spending more than what is needed that's why your wife feels it's ok to splurge. If she doesn't have the concept of budgeting and saving for your future, be the one to initiate.