Would my manager ask me for proof?

So I work at Burger King. I work every single weekend now. it's getting to the point to that I'm getting very mad. I used to use my weekends to relax, de-stress myself. I have college to worry about & my crazy life. So I was thinking of telling my manager that I got another side job to work only weekends to get my weekends off again. Would I need some type of evidence to demonstrate them that I have another part job?? Some one can give me a gussestion?