This may sound strange but... Go out with her, be her wingman and set her up with someone. You won't feel as bad about it as you have some power over the situation and unconsciously feel it was you who made her do it, not her doing it despite you. It's easier to move on and feel less attracted to her when you act up in yourself not to want her so much so you're willing to help her find someone.

It's a double edged sword. It's like the ultimate DHV, shows confidence, you're fun to be around, you're showing a lack of interest and all this culminates to an intense attraction to you. Meanwhile you're actually forcing her out of your head which makes you less interested.

The question is how long are you gonna be living in this house? If only temporarily (most likely a year or less?) why the hell not? If shit goes sour it's not like it's gonna stick with you for the rest of your life. I'd do it... if you genuinely want to do it. These are the types of things you regret down the road.

Just seems like she wants to get at you, dude. It's girl drama... Just ignore it and move on. Let her do what she's going to do and act normally. You have no control over it, the only control you have is your direct involvement: Will you or won't you be involved? I would say don't be involved at all. Let her carry on and wash your hands of it.