Peony, thanks for starting this thread and you give good advice.
I identify totally with what Smileless says about the waves of hopelessness, sleepless nights, long dark tunnel and feelings of despair. I also agree with the poster who says that reconciliation may come when you least expect it and when you stop pushing for it.
I am semi-reconciled with DD now, but there is still a long way to go and she has hurt me so badly that I think I am always going to be a bit wary. To be honest, I think a little piece of me has, if not died, then certainly frozen over, in order to protect myself. But I do feel much stronger, I have stopped beating myself up about what I did and didn't do to cause the estrangement. I am moving forward positively but cautiously and enjoying all of the positive aspects of my life, including my relationships with my other two lovely children. I realised that ESD was taking up too much head space and that I was spending far more time thinking about her than the two who were so loving, supportive and loyal, and that's not fair on them.
So, yes, let's embrace Peony's message and not waste our lives on things that we may not be able to change. Let's count our blessings and enjoy and be grateful for what we have.