Truth why she left me

When got together we had nothing. We went out often with time we built a place to call home and settled down. Didn't go out, started to invite less friends. Most of them where my friends. Her friends were far and visited rarely. She started to feel lonely. I work every other weekend. She asked to call them over but I didn't feel like it. She said she's sad when I work because she's alone at home. When I was off and she worked I cooked, cleaned, did laundry, shopping. I was busy. So I didn't think much of it. I thought she's just bored. But it dragged on and on. Eventually her parents moved to UK and stayed with us. I thought she's going to be happy. But mom being mom here and there started to tell her what and how to do. So she got even more lonely with no one to share how she feels. She started having a drink almost every day, smoke. I hated it. So on two occasions I didn't speak with her for 2 days. She cried. I was heart broken but thought that will prevent her from the habit. I tried to deal with the consequence rather than reason of it. Second time she said she doesn't love me anymore. I stumbled upon last resort technique. Had to give her space for a month. But by doing so I just inforced her solitude. I really believed I did everything in my power to make her happy. But failed. She did tell me she still loves me but only as a friend. That I'm very special for her, that she won't find anyone so great but she needs to be alone. Else she will be unhappy for the rest of her life that she didn't try. She even doesn't want her parents with her.

We can't terminate the tenancy. So I should move away and she would stay with parents. She still won't be alone and might run away in someone's hands to get away. He'll save her. So I will be not needed.

I can offer her to move out alone and stay but than I'll be the pain which she left and I'll have no place in her future. Staying won't help. She might move on with someone else while I'll stay behind in pain. Same if parents move out. Either way I lose.

What should I do? 

I want her to be happy, I'd let her move out. But I'm afraid that will be it then. The hope that I might get her back gave me strength but now I have nothing.