I feel normal now lol
With my previous car, I had spent loads on mods. I also used to have different forum members come over most weekends to have some work done on their cars.
On the odd occasion that my mrs went in my car (or even looked at it), she would notice things had changed, and when she challenged me to how much it cost, I would just say "Bob gave me that for working on his car", or "John said if I can fix it I can have it".
Seemed to work