Tell each of them your clear wants, needs, and limits.
Could tell the GF not to come on to you. That's against your own code and she could choose to date less "potentially messy people" than her bf's roomie! Or ask YOU to date in a potentially messy situation like that knowing you live with her BF and it could arouse jealousies and so on. Esp if you cannot afford to live alone or move -- that's putting your domestic stability at risk for what?
Being your friend/roomie wing man -- well, could ask the GF how she feels about that if you are willing so everyone is clear about personal boundaries. Are YOU a part of the DADT policy? Because you live there and witness whoever coming around? But since you do not sound comfortable -- don't wing man. Saves grief all around to just not do things you are not really willing to do. A "yes" is a "yes." A "maybe" or a "no" is a "NO."
And if you wish to be free of shenanigans, could choose not to get involved with either one of them as a dating partner or as wing man at this point in time or get sucked into the middle. It's too close for comfort, dude. Roomie? It's the same as workplace.
Don't need to be inviting needless drama into your life. You are responsible for your own best healths.
Last edited by GalaGirl; 02-13-2013 at 06:05 AM.