I have been listening to a tape series by Andrew Wommack titled God's Kind Of Love Through You.
His main point is to not let others control you and to always walk in love. That is incredibly hard when you go through the rapids as I have noted here (including ongoing rejection), but I have to agree that it is vitally necessary. This is a good point, whatever your general view on the rest of his teaching or even Christianity in general.
Keeping that love focus is the only way to be open for your children. While it can be hard to believe, they really do need you, even while they are rejecting you. You need to stay in love so that you can be their (in love) when (or if) they decide to return.
This doesn't mean this is easy. It is harder to let things slide when the slide tends to go into a wall!
Nevertheless, you need that love to continue to guide you for your own sake, even it not for them. Holding the hurt and bitterness is not helpful, though it can be incredibly hard to figure out how to not let it rise up with each and every offense, many of which remain intentional.
This is not the road I would have picked, but since I am on it I will keep following it the best I can!