Okay to clear some things up,

He works with this girl, and she is engaged to another guy who is long distance right now. I can't live with him because I'm currently living close to my job which is a little too far from his job and he needed a roommate and she happened to have a spare room in her house, rent free, if he would watch her dogs when she's out of town and help with groceries. It seemed like a good set up and he asked so I said yes. I felt like saying no would be bitchy. I don't want to be a controlling girl friend.

So now I feel really jealous over it. Which I feel is irrational.