No one is telling you to pretend that everything is all happy, happy. You are going to have days when everything sucks, experience those feelings, allow them to wash over you and move on once they have passed.

I would advise you to do the following:

1. read and educate yourself on MLC and depression
2. leave the ow alone, stop bringing her up in conversations
3. no relationship talks right now
4. you cannot3 control or manipulate him or the affair
5. allow the affair to die a natural death on its own
6. focus on you and your family
7. find things to do to keep you busy
8. work on you
9. get yourself checked out by a physician (I wouldn't take his word on what he said about the sexual relations issues)
10. live your life to the fullest

Above all else, I wouldn't believe anything that he told me until he fully wakes up and the ow is completely gone, i.e., no calls, texting or seeing her. He would have to prove to you that he loved you and wanted to return to the marriage. He has a lot of work to do and until he can do that, I would look at him as a roommate and live my life to the fullest.

Sit quietly, the answers will reveal themselves when you least expect them to.
The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.