Perhaps I'm taking this a little seriously (not the first time!) but am I alone in thinking that it's a very bad idea to ask your roommate for sex or to even hint at it?
Mr. Robinson, so what is your living arrangement? Do you live in a boarding house?
When I hear roommate it makes me think of college and someone in the same room. What are you sharing with her? Kitchen? Bathroom? How is she your roommate?