She's Dead to Me

Last Nov I moved in with someone purely out of necessity, but also to give the relationship another go.  I have not been happy nor content.  I don't see a future with this person.  Shortly before I moved in, a week prior his neice and her daughter moved in.

The house lease was kept in the neice's name as well as the bills becuase she was living there before leaving and living with her boyfriend for a year-so my friend (her uncle) stayed there and continued to pay all the rent and bills.  When she moved back in she told him she would only be there for a short time however, I have been watching her actions over the last six months and finally said something to him.  Her pictures and shit are all over the house.  She recently had someone lay rock on the back porch for her.

When I mentioned I was buying a treadmill for the front porch, she went out the next day and bought a "gift" of a table forherself to put there.  Her uncle and I were sitting in the living room,  I told him to look around and see that she's not leaving.  She never planned on leaving and she's been insisting on paying the bills since shes been there.  (She is still taking money from the boyfriend she left).  This is what she does.  I told him she is now "dead to me".  This is how ive been my whole life, I don't give people 2nd and third chances. 

I'm at a crossroads now.  I don't want to get a place with the uncle, and I have to tell him.  Ive been looking at apartments for weeks now.  But, I'm scared and I feel an extreme amount of guilt.  Half of me says stay and try and work things out-but the other half wants something for myself for once.  Don't know what to do.