It's happening where I don't want it to: anything else I can do?

Six roomates: two guys, four girls. All between the ages of 22 and 26.

I've lived here a month. Started a new position, and found this place on Craigslist. It was a mile down the road from work, and it was forcing me to be around others my age.

The roomates are all overweight, with the exception of one of the girls. She's one of the guy's girlfriends - kinda cute raver girl. But no more than a 7 at best. We threw a party last weekend. A lot of people, who all knew each other. I was the odd one out, but I tried, and was a smash hit, apparently.

A few times, drunk girls would comment on my fitness. At one point, a girl even pulled my shirt up. Raver girl and her female friend liked what they saw and dragged me into her room, where they stripped and proceeded to fuck each other in front of me.

I have a lot of respect for drunk me. He does some stupid shit, but he knows where the limits are. On top of me having a girlfriend that's actually cool shit, this would be shitting where I'm eating.

"Sketti-os, where are you going?"

"This would just cause problems."

We had a chat about it in the morning, and I made it crystal clear that I'm not going there. She's a roomate, so if shit hit the fan, my daily life would be affected. She seemed to agree, but what she did next didn't coincide. She broke up with boyfriend-roomate, apparently claiming she wanted to see other people.

Another roomate is mad at me because I (politely) rejected her 360-pound cousin who was rolling balls on molly all night. Not really my thing.

Question 1: Boyfriend roomate doesn't know this happened. Do I tell him? I feel like that's the honorable thing to do. Not to mention, it would save my ass if raver girl tried to lie about anything. But at the same time, it would piss off raver girl and cause problems there. But if I don't, and boyfriend roomate finds out later, from another source, I imagine it'd be worse. If my girlfriend tried to fuck someone, I'd be thankful if they told me.

Question 2: Other than making it abundantly clear verbally that I'm not shitting where I'm eating, can I do anything else to remove the sexual label given to me by the roomates and their close friends/family, or do I constantly have to be on guard?