I agree with everyone who said "don't let her move in". You have a right to set a healthy boundary. Understanding bounderies is another aspect of living a healthy life and expecially a polyamorous one. Boundaries can get confused and easy in this lifestyle! I would not allow someone to move into my home unless I feel a love for them as well as great trust and respect.
I have noticed that people (me included at times) tend to get involved in a monogamous relationship for all the wrong reasons. One of those reasons is because they have met someone who is willing to become sexual with them. I don't think that is a good reason. Also- on the other hand- finding someone who is simply willing to enter a poly relationship is not reason enough to enter into a relationship with them. And- letting someone move in with you because you feel sorry for them is a terrible reason for asking someone to move in..... just my thoughts.....continue to honor yourself Firedancer.