Mate, your shrink has hit it on the head. You can do so much to try and help those you love, but at some point, you must detach and let them live their own lives, make their own mistakes, and learn for themselves. Yes, it people often hurt others during the process, but it is life, and there is little we can do to change these facts. People must learn for themselves.
I think you have done what you can do, and you have suggestions in this thread for any last attempts at saving your relationship, but if things have just failed, then you do need to come to terms with this and move on with your life. A little you time is needed I think, to get yourself better from these few symptoms you have, and get yourself back on a more positive path to your life. The best thing you have done, is talk about all this, and not keep everything to yourself. Well done.