I had this issue with my ex wife for almost all hobbies I ever got into (except when I was playing tournament paintball, strangely). It wasn't ever about the money, always the time. Got into a lot of disagreement because I was her only hobby. She never minded the system I had in my car when we were dating, though.
She never understood that as a husband and father, I had to fulfill the needs of 3 roles (husband, father, individual). The second one of those gets neglected, the other two suffer. It's the same thing they tell you about crash landings on an airplane, if you don't take care of yourself, first, you're of no use to anybody else.