I don't think what happened to you is uncommon. I think part of her wanted it to work out but the feelings weren't there the way she wanted them to be. It's very common for couples in trouble to but a new house hoping that it will bring them happiness. My ex gave me a anniversary card at the end of June saying "thank you for the best 15 years of my life and I look forward to many more". Then bombed me in July. WTF happened in a month? The truth is she probably wrote what she did because she thought it was the right thing to do and she maybe wanted to believe it. Don't spend another minute thinking about that letter. My advice to you is let her go. I can 100% absolutely promise you that being divorced is better then how you are living right now.