I dont think its your ego that keeps you from taking her back.
The act of cheating is one of the most painful forms of betrayal. I have read that it hurts more then death. When some one cheats, they hurt you emotionally, but also have the potential of impacting your physical health through very dangerous stds.
There is a lot to think about. So you are smart to have doubts. It is wise for you to not take her actions lightly.
