<human>: Could you distill the essence of the text into 1-3 sentences?

So I started hanging out with this girl a couple of weeks ago.  It seemed as if we were hitting it off right in the beginning, she'd come over, hang out, and watch movies with me all night.  Everything seemed to be going well until she met my room mate a few days after we'd started hanging out.  From that point on she seemed to pull away from me and begin to gravitate toward my room mate.  I was a little weirded out by the situation but kept my cool and just let things go as they did.  A couple of nights after she met my room mate she ended up sleeping in the same bed as him, which mildly irritated me.  Since then she's been coming over and staying with him nearly every night.  I expressed my interest to her and my room mate both.  My room mate before the night they slept together, and to her afterward.  Anyway to the point of the post, I'm pretty irritated at the both of them due to the fact that she's coming over every night and I have to be around it.  Am in in the wrong to be angry with them?  Any suggestions on how to handle the situation?  Thanks in advance.
<bot>: Girl I was interested in started sleeping with my room mate, and I'm pretty irritated with the both of them, am I in the wrong to be angry? And any suggestions would be appreciated.