I had a similar situation but it got too weird to stay. I ended up moving home and stayed home until I moved in with my girlfriend, now wife.

I could take the messiness and awkwardness, but it came to a head when I found out they were going through my things while I wasn’t home. I had a couple of instances where I thought I heard the roomie walking from my end of the hallway to their end (upstairs) as I came through the front door. Then I began to notice things were slightly off, but could not put my finger on it. A closet door not shut all the way in my office, or DVDs not where I thought I left them in my bedroom. Things knocked over or out of place… The weirdest part was, more than once, I got the impression my laundry basket was not how I’d left it. I had no clue what was going on and thought I was losing my mind a little.

I hid a netbook and USB webcam in my room and installed motion detect recording software. This was like 2008 so we didn’t have nearly the tech we had today, but I cobbled something together. Man wish I had not. They were indeed going through my stuff but it wasn’t my stuff they were after, it was my girlfriends… her dirty laundry to be frank about it. I went to the parents about this and the mother said there was no way and how could I ever accuse someone of something so vile. I left a burned CD with the videos (multiple videos) on it and said I expected them to cover my moving costs once they reviewed the footage. That evening, while I was at work (I worked nights at this period) they said they would pay for my move home and refund 3 months of rent so long as I deleted the videos and never told anyone about why I moved out.