<human>: My girlfriend and I have been living together close to two years and recently we've fallen on some rough times financially. She doesn't make nearly as much as I do and so I've helped her with rent for four months or so, paid it entirely the past two.

Recently my other housemate's rent money given to me (in hundred dollar bills) has suddenly disappeared. We're incredibly messy so it's certainly possible its misplaced. However, I found a $50-100 item while I was looking for the rent money, and  it seems she bought it recently. Then, a couple days ago, she went to the store with friends and bought $50 worth of alcohol with a hundred dollar bill (i saw the receipt while helping her bring the booze into the house. Yes, I'm hurt that she's buying these things when she should be contributing but that's something I can discuss with her later.

She just got paid in check form when this happened and she usually deposits it, so why would she take out a hundred dollar bill when she prefers her debit card?

I don't think I'm being paranoid. I am just losing so much money helping her and now this rent money disappearing...

I know I need to talk to her, but she can be super defensive. How do I bring this up without this entire relationship blowing up?

Can you condense the text into a few key points?
<bot>: My girlfriend is spending money I thought she didn't have with what I think is my money. How do I ask her where she got it?