The guy I have been dating for a month now is great except for one thing, his roommate is a woman. I find myself having a problem with this even though he says all they are, are just friends. Now this is not like they are sharing a rented apartment or something. She lives in his house and pays him rent.

She is gorgeous and flirtatious (with all guys) and each room in his house seems to have a bit of her touch, which is a reminder to me that she is around.

Am I being petty here or do I have a point and should pursue it with him?

Honestly, unless you have a reason to suggest that he is hooking up with her why is it that big of an issue? People have Co-ed roommates all the time, and if you trust your boyfriend enough it shouldn't really be an issue.

I think the bigger issue that's there is that if you don't have a reason to claim that he is cheating on you, you trust him enough that he wouldn't cheat on you, then what is the real reason behind you not wanting her there?

Just something i'd look into on my end personally if I was in your shoes is what the reason for the emotions you are feeling are. I have lived with all men before myself and there were never issues with the girlfriends (one was my brother - so obvious reasons there, but the other person was not related to me whatsoever)

I think the flirtatious thing - some people do it on purpose, and some it is just a part of their personality. If you have no reason for her not to be around one thing I would suggest is talking to her - letting her know that she comes off very flirtatious with your boyfriend and it makes you extremely uncomfortable - that if she would try her best not to be that way with him specifically.

Why don't you try just waiting and see what happens?
If they have something together I suppose you will notice (usually women do).
I don't think that arguing is a good idea for the moment...

Maybe you are making more of it than there actually is? You need to trust the guy that you are with - if you can talk to him openly and honestly then communicate the problem in either a rational manner or jokey way. Do not start a fight or throw accusations for sure otherwise you will be the one who is the bad guy.

In a relationship, Trust is one of the most important things to make the relationship works. In that kind of issue you should try to be open to your boyfriend on what you feel. You should trust your boyfriend in this kind of situation.Don;t make him feel that you are jealous or you doubt his loyalty to you. Let him feel that you trust him and for sure he wont do anything bad or break the trust you gave him.