I think you're starting to get it intellectually, but it takes time for your emotions to catch up. It's that pesky withdrawal from co-dependency. Try to remember and concentrate on who you were before you met your W. Take the best of that person, and work on the rest.
Before the bomb was dropped on me, deep down I was very unhappy with myself, so when the bomb was dropped, a part of me wasn't surprised at all. Terrified, but not surprised.
Detachment and no contact help, because you don't have to have that front up. It is exhausting, and you need your energy to work on yourself. Since you're still living with your W, you have a tough balance to maintain. Try to give yourself breaks from her. I think going to the party alone was a great thing for you to do.
