End Game: Crime Perfeito

I spent almost two hours watching a movie that I thought, with all the good actors in it, would be worth watching. I couldn't believe it when the movie ended and I had absolutely no idea what had happened.....I was mad because I could have used that time doing something else....I tried to figure it all out, but really had no clue. Thanks to those who figured it out and have explained it....right or wrong, it's better than not knowing anything!! Who was the lady in the movie with dark hair that we saw a couple of times driving away? How did First Lady know that her husband was cheating on her? At the end of the movie Kate said she would eventually find out the truth. Does this mean that we're going to be subjected to End Game 2?