Married guys - car budgets and honesty

My wife and I have a common savings account where her checks go.but I never put my check there,opting instead to pay all the utilities and mortgage with my check once it's cashed.She doesn't make much-and would probably cringe if she knew what I've put into the car even though it isn't THAT much. I have maybe $4000 in my Dart,mostly it's in the drivetrain as the body is "Northern"-$2000 of which was the initial price of the car. I work 50 hour weeks compared to her 20-25 so I think what I spend my money on (AFTER the bills are paid) is my damned business .Besides,MOPARs are a sickness to which there is no cure and she knows that.