I also did a bad thing last night, after he left I called him and apologized for any hurt he was feeling . . .
WHY?? Why is HIS hurt, YOUR responsibility?
His hurt, in this instance, is due to the disapproval of his co-workers towards him. Which is a DIRECT consequence to his infidelity and his own selfish, boorish behavior.
Can you see where this is NOT your fault, and NOT something you need to apologize for???