I am sorry about what you have learned. Your IC has given you good advice - detach, detach, detach.
This will eat you up if you let it. Listen, if you are able - stay away from your W, don't talk to her, don't snoop, and keep yourself busy.
Do you have any friends that can come over, or guys in a small group that you can talk to? Get someone that you can trust (hopefully someone that doesn't know your W), and dump all of your emotions on him. This isn't going to go away. For now, just minimize the damage to yourself.
