Weekend with a guy, I need advice?

So my roommate and I are travelling a state over to see a guy that I am sort of "dating" I guess you could say.. it's a complicated situation lol.. ANYWAYS.. My roommate is of course coming with me, and her fiancee is unable to come too so she is basically going to be the third wheel. I can't make the road trip by myself, but I'm afraid it is going to be super awkward. I don't know what I should do or how I could make things seem less awkward when we are all together. I mean she has no problem with PDA or anything happening while she's in the same room: we've already talked about that haha.