Search Results: sleeping with my best friend's brother

So, I started uni this September. Eventually the only option that turned up was living with 5 guys that were a year older than me.

Most people would think that’s insane but I have always gotten on a lot better with guys over girls, mostly because I grew up with two brothers, I’m quite outgoing and dislike the kind of drama girls get themselves involved it.. so as a result most of my friends are guys so.
After about a week, I got together with the guy I was living with that I fancied. After the first night we spent all of the following day together and then from that week on we slept in the same bed together up until now, his bed. It’s now been six weeks of us sleeping together and cuddling/hanging out with each other during the day.
Recently, although he hadn’t done anything to make me question him, I started to get nervous and feel like he was losing interest in me even though I don’t think he was acting any differently. So I decided to test him a bit, so I was going to bring up the topic of whether or not we were seeing other people after we got home from a night out.
But, while we were out my other housemate was trying to set me up with other guys although he knows I have been seeing his best friend for the past while, I thought it was odd that he was doing this and then I started to wonder does he know something I don’t?
Then later that night in bed, I asked the guy I was seeing “how would you feel if I was with another guy some night?” he said I can see other guys if I like but that he wants to know who they are if i do, but over all he acted quite calm and not too bothered.. so now I am panicking because I assumed he would ask me not to see other people but when he didn’t I felt like all my fears were true and maybe he really was losing interest?
Am I just an easy option for him because I live with him?
since this happened he has continued to act the same as he always has with me but I just can’t help but think my instincts are right.. what do ye think?