The best way to get a handle on your finances is to have a budget and then execute that budget. It doesn’t help to plan the work of fiscal responsibility, if you aren’t going to work the plan.
Typically, a plan should include the total income and the total expenses subtracted from each other to create an overall zero balance. I blew off the dust from this one-month budget from years gone-by.
You can set this up in Excel.
If you can get a handle on your finances, you will have one less reason for your relationship to break-up.