Help! My girlfriend thinks she's stuck..is she???

My girlfriend has a house with her boyfriend and now she wants out. I know they aren't married but I thought folk on this board would kow best. She thinks he's been cheating because out of 7 days of the week, he's home one. They argue alot so she's just at her wits end. To make a long story short, he doesn't want to sell and he won't move. he just wnats her to be miserable. Can she take him to court to make him sell?? What options does she have?