My daughter has been estranged from me for two years and I wonder how other people deal with this. She has written 5 pages to me telling me what an awful mother I am but at the same time thanking me for all the things we did before she married. We were very close at one time.

Me & my mom have awful relationship with each other most of the time. I did the same thing, I would write her letters & tell her how rude & mean she is to me. She would always act like I'm not there. I could be dead & she wouldn't notice. So I started to run away to prove to her one day I could end up not being there & she tried to send me away. The reason I did it was because I felt like she paid more attention to everything else but me. & I don't know you really well to give you an exact answer, but if you're married it could be you pay more attention to him, or your work. Or she just feels you never show her love. I'm sure you're a wonderful mother. It's just you're kids will never see that until they're much much older.

Perhaps you disapprove of her husband?
I didn't have children, but didn't get along with my mother. I made a few attempts to talk with her adult to adult, but she quickly squashed any conversation.
I would write her back, and ask if you can talk. If my mother could have acknowledged one little thing that hurt deeply I would have opened a spot in my heart.
I did realize at some time in my life that she was equally hard on everybody (I was the youngest) and that she was miserable with herself.
I realize that this probably has nothing to do with your situation. But how about that husband of hers? Is that when it started?

Firstly I'm sorry your relationship is strained at best. But there may be something in her marriage where she feels you're a safer target than anyone else. Judging by when you said you even were close at one time seems something has happened between you at some point even if you can't see it or think it as significant. I don't know if where I'm thinking is correct but my mother and I have and are extremely close but for a time there when I was engaged I had a tough time with my partner my mother knew something wasn't right and even though I was overseas at the time I pretty much kept her isolated from my personal life and she persisted with me. I almost got to the point of hating talking to her so I could maintain my secrets and be the adult in my life. After a time I got my things together and I've slowly shared what was happening and going on. For you I would suggest reinforcing you love her and want to work on your relationship. Id even suggest an impartial third party to hear you both out. I don't know if what was in the five page letter was accurate or an altered perception of what was happening at the times she wrote about or things you didn't tell her as she was a child, but I would think she may be seeing it as a bad time for her you caused or didn't tend to at her idea of importance and speed. I read your note to my mother and she said look for a theme she keeps going to or relying on in the letter as an over all either she's hurt, angry, ignored, discovered something you didn't tell her or something totally different. If you feel this is too hard to address with her I don't know your relationship with her husband but maybe see if he can illuminate what is going on but be warned she may think this action is underhand. Try even seeing if she will make a meeting with you for lunch at a non personal location and try and talk don't make it her house it has to be a neutral ground then no one has the power position. If she agrees try talking about one thing at a time and don't be attacking or submissive either be the mother and just listen. I personally suspect she is getting outside information challenging your parenting or her memories. I think in truth the husband and her marriage may have something to do with it all, seeing as she was so thankful of your help in that extremely stressful life event. For you Id try and think if she's changed since her marriage or even see if she is angry as a rule with anyone else or if its solely on you. Be honest with yourself on any of her issues if there is a blame you need to own then do it , my mother apologises as often as I do for our past bad or misguided decisions that have adversely effected each other and its clean house regularly for us. The older I get the better I can appreciate her choices even if not the best they created the best possible starter me by learning not to do the things she did or do them, Just open a line of communication and remember listen don't be defensive or angry, just listen. Then if this doesn't work even as a start you may need some professional relationship help, no ones got the answers all the time and we are never always right, as they say a broken watch is right twice a day. Hope this gives you a leg up and helps a little sorry its so long. Goodluck