As you analyse the times before you caught him, compare it to the period you struggled through the betrayal, you have learned many things. Many things about yourself.
The life you lived during the time he was rolling on soiled sheets will not be discarded just because he came home.
That wife who always had dinner on the table as he came through the door, who did the laundry and insured he always had an ironed shirt is gone.
You will never be that secondary character again.
You will think of yourself first. Then him.